A sliding assistance mechanism for helping a switching operation of a moving body on a main body side, includes a case attached to the main body side; first and second moving members slidably placed in the case, respectively; a pair of latches pivotally supported at each moving member, respectively, and releasably locked to corresponding parts of a case side; an urging device provided between both moving members; and a guide groove provided in the case for moving the latches along the same; and first and second operational members spaced apart from each other and provided in the moving body. When the moving members are at a halfway position, an engagement of one of the latches with the second operational member provided in the second moving member is released, and the moving body is pulled by the urging device to the second position.