In an image forming apparatus including a fixing unit and a storage part, the fixing unit includes: two rollers forming a fixing nip part; a pressure adjustment mechanism varying fixing nip pressure; one driving input gear receiving: a rotational power in a first direction for driving the two rollers and a rotational power in a second direction for actuating the pressure adjustment mechanism; and a gear cover supporting, with a long hole, a bearing supporting a rotary shaft of the driving input gear. The gear cover has a convex part, and the storage part has a receiving part supporting the bearing of the driving input gear at time of insertion of the fixing unit. The receiving part has a concave part fitted with the convex part of the gear cover moving with respect to the bearing of the driving input gear at the time of insertion of the fixing unit.