PURPOSE: To provide a rubber member fitting device which is to push in a rubber member having flanges detained with the two surfaces of a plate-form work into a mounting hole provided in the work so that mounting is made, with which mounting of the rubber member can be generated always correctly with a specified intrusive amount.

CONSTITUTION: A guide 3 has a guide hole 3a opening toward a mounting hole 1a and confronts one surface of a work 1, and a pressing member 4 for intrusion of a rubber member is furnished in such a way as advanced and retreated to/from the mounting hole 1a within the guide hole 3a, and a tapered portion 3b with the open end made in a minor diameter is provided inside the opening of the guide hole 3a.