NOVELTY - Continuously producing monosilane using monosilane production apparatus which comprises reaction column (1), at least two upper condensers (3), bottom reboiler (8) of reaction column, and evaporation tank, comprises: supplying e.g. dichlorosilane to upper stage of reaction column; supplying catalyst to upper stage of reaction column; introducing resultant mixture to upper condensers; separating monosilane from condensates; recycling condensates through reflux feed pipes (6) to upper stage of reaction column; and bringing condensates into contact with catalyst in reaction column.    USE - The process is useful for producing monosilane (claimed) which is used as a raw material for epitaxy of silicon with a high purity and for amorphous silicon for solar cells.    ADVANTAGE - The process provides: continuous production of monosilane; monosilane rich gas comprising more than 60% (preferably more than 80%) of monosilane; reduction of feed flow rate and byproduct silicon tetrachloride flow rate and at the same time reducing logistics and byproduct materials; reduction of reactive distillation heat load; reduction of column vapor load resulting in a reduction of the reaction column diameter; reduction of column liquid load, catalyst and hydrochloric acid injections; and reduction of the recycling trichlorosilane flow rate.    DETAILED DESCRIPTION - Continuously producing monosilane by a monosilane production apparatus which comprises a reaction column (1), at least two upper condensers (3) each of which has a reflux feed pipe serially connected to a top portion of the reaction column, a bottom reboiler (8) of the reaction column, and an evaporation tank connected to a bottom portion of the reaction column, comprises: supplying dichlorosilane (preferred) or a mixture of tetrachlorosilane, trichlorosilane, dichlorosilane and monochlorosilane to an upper stage of the reaction column via an upper feed injection point (9), where the ratio of the number of total hydrogen atoms to the number of total chlorine atoms is 0.6-3; supplying a catalyst to the upper stage of the reaction column via a lower injection point; introducing a resultant mixture containing monosilane, monochlorosilane, dichlorosilane and trichlorosilane from the top portion of the reaction column to the upper condensers; separating monosilane from condensates containing monochlorosilane, dichlorosilane and trichlorosilane in the upper condensers; recycling the condensates through the reflux feed pipes (6) to the upper stage of the reaction column after separating monosilane; bringing the condensates into contact with the catalyst in the reaction column, where a monosilane rich gas including monosilane as the primal component by molar basis is produced via a pipe connected downstream to the upper condensers.    DESCRIPTION OF DRAWING(S) - The figure illustrates a schematic diagram showing the apparatus to be used in the process for the continuous production of monosilane.    Reaction column (1)    Upper condenser (3)    Reflux feed pipe (6)    Bottom reboiler (8)    Upper injection point (9)