NOVELTY - Immunoassay apparatus (I), has recovery unit, ultrasonic crushing unit having first collection receptacle, luminous-reaction apparatus for reacting the antigen-antibody complex generated by the immunoreaction with light-emission reagent, second collection receptacle containing the antibody, light-emission reagent injection unit for measuring the luminous-reaction, where the immunoassay of the microorganisms is automated by operating luminous-reaction measurement unit, to measure the luminous reaction.    USE - (I) is useful in immunoassay for measuring microorganism e.g. coliform bacteria in sewage water.    ADVANTAGE - The method is automated, cost-effective, highly accurate, rapid and quantitative.    DETAILED DESCRIPTION - Immunoassay apparatus (I), comprises:    (a) preprocessor containing recovery unit, filtering unit, concentrate production unit, ultrasonic crushing unit, immunoreaction apparatus, luminous reaction apparatus, a movement apparatus, and a control apparatus, where the recovery unit recovers the target microorganisms in a reaction liquid from the sample solution containing target microorganisms; ultrasonic crushing unit crushes the recovered microorganisms and diffuses the antigen in microorganisms into the reaction liquid; luminous-reaction apparatus reacts the antigen-antibody complex generated by the immunoreaction with light-emission reagent; movement apparatus comprises control unit which controls the apparatus and automates the immunoassay of the microorganisms; filtration unit filters the sample solution and captures the microorganisms on the filtration membrane; concentrate production unit diffuses the microorganisms captured by the filtration membrane in a reaction liquid, and generates the concentrate; ultrasonic crushing unit having the first collection receptacle to which the concentrate is injected, and ultrasonicated; immunoreaction apparatus has second collection receptacle to which an antibody is fixed to the inner wall and acts as a solid-phase antibody; nozzle portion for attracting predetermined amount of the reaction liquid containing the antigen generated in an ultrasonic crushing unit, and for injecting into a second collection receptacle, labeled antibody injection unit which injects labeled antibody into a second collection receptacle, shaking unit of second collection receptacle; luminous-reaction apparatus has a washing unit for washing the second collection receptacle; light-emission reagent injection unit for injecting the light-emission reagent into the washed second collection receptacle, and a luminous-reaction measurement unit; control unit for detecting whether the sample solution is filtered in the filtration unit, moving the filtration membrane to the concentrate generation unit in the movement apparatus, to produce microorganisms concentrate, and for detecting whether the concentrate is injected into the first collection receptacle, and ultrasonic generation unit is operated;    (b) member for recovering microorganisms in which the microorganisms captured by the filtration membrane are mixed with a liquid;    (c) dispersing plate which contacts with the filtration membrane and distributes microorganisms;    (d) disc unit which has the holder unit attached to the orthogonal direction with respect to the dispersing plate, where several holes are formed in the dispersing plate, and where within the first collection receptacle, the dispersing plate for microorganisms recovery is made to contact with the filtration membrane in the reaction liquid, and the microorganisms and reaction liquid are mixed, where the immunoassay method involves detecting the completion of the ultrasonic crushing, operating the shaking device to perform the first reaction, after injecting the reaction solution into a second collection receptacle, the first nozzle was operated and the antigen is diffused, after detecting the completion of the first reaction and operating the labeled antibody injection unit, the shaking device is operated again and second reaction is performed, the completion of the second reaction is detected, the second reaction container is moved to the luminous-reaction apparatus by a movement apparatus, after washing the second collection receptacle with washing unit, the light-emission reagent injection unit is operated and the light-emission reagent is inject into the second collection receptacle, where the immunoassay of the microorganisms is automated by operating a luminous-reaction measurement unit and measuring a luminous reaction.    DESCRIPTION OF DRAWING(S) - The figure shows outline block diagram of immunoassay apparatus. (Drawing includes non-English language text).    Filtration unit (101)    Concentrate production unit (102)    First collection receptacle (103)    Ultrasonic generation unit (104)    Ultrasonic crushing unit (105)