NOVELTY - The apparatus (1) has processing tank (10) for mixing waste material with microbial bed so as to carry out fermentation process. A cover (20) is pivotally supported on processing tank so as to open or close an opening portion (11) of processing tank. The deposit adhered to inner wall face of processing tank or cover surface is removed based on movement of removal portions (51,52) which are moved in response to opening/closing operation of cover. The cover and removal portion are interlocked by link mechanism (43).    USE - Apparatus for treating waste material e.g. pressed dreg such as organic refuse, dead leaf, hay grass, fruit juice and sludge.    ADVANTAGE - Since the dew condensation water adhering to cover surface or processing tank is removed, or the deposit is collected at the time of opening and closing of cover, the generation of offensive odor of putrefaction due to dew condensation water can be eliminated. The weight reduction treatment of waste material can be performed within short time. The deposit can be removed easily and completely. The increase of processing load of waste material treatment apparatus can be prevented.    DETAILED DESCRIPTION - The apparatus has cover having latching portion which is latched with forward-backward movement portions (41) of link mechanism. The forward-backward movement portions are urged by coil springs (44a,44b) towards direction spaced apart from cover. The microbial bed is injected into inner tank section (12) of processing tank and outer tank section (13) is located at preset distance from outer surface on inner tank section. The removal portion is connected with link mechanism and protruded towards inner side of processing tank. A heater (17) is provided in lower portion of processing tank, for heating dew condensation water produced during fermentation process of waste material.    DESCRIPTION OF DRAWING(S) - The drawings show the sectional side views of waste material treatment apparatus with cover in fully-closed state, half-opening state and fully-opening state. (Drawing includes non-English language text)    Waste material treatment apparatus (1)    Processing tank (10)    Opening portion (11)    Inner tank section (12)    Outer tank section (13)    Heater (17)    Cover (20)    Forward-backward movement portions (41)    Link mechanism (43)    Coil springs (44a,44b)    Removal portions (51,52)