An image forming apparatus comprising: an apparatus body; an image carrier unit that includes: a support member; and an image carrier that is arranged to be rotatably supported by the support member so to move in a direction and directly or indirectly carries images; a plurality of rotating bodies (25, 33, 34) which are provided in the apparatus body, are rotationally driven independently of each other, and configured to apply forces to the image carrier unit, the forces being based on rotations of the rotating bodies (25, 33, 34); and a control unit that is configured to control driving states of the plurality of rotating bodies (25, 33, 34), characterized by a positioning part that is provided at the apparatus body and is configured to position the image carrier unit by being abutted against the support member; a pushing unit that is configured to push the support member in a normal direction opposite to the moving direction of the image carrier towards the positioning part; wherein the control unit is configured to control the rotating bodies (25, 33, 34) so that a resultant force of forces applied to the image carrier unit from the plurality of rotating bodies (25, 33, 34) is always applied in the normal direction where the support member is abutted against the positioning part, at least in one of the following periods: a period where the plurality of rotating bodies (25, 33, 34) moves to a normal rotation state from a stopped state, a period where the plurality of rotating bodies (25, 33, 34) move to the stopped state from the normal rotation state and a period where the plurality of rotating bodies (25, 33, 34) are made to be in the normal rotation state and image is carried on the image carrier. an apparatus body; an image carrier unit that includes: a support member; and an image carrier that is arranged to be rotatably supported by the support member so to move in a direction and directly or indirectly carries images; a plurality of rotating bodies (25, 33, 34) which are provided in the apparatus body, are rotationally driven independently of each other, and configured to apply forces to the image carrier unit, the forces being based on rotations of the rotating bodies (25, 33, 34); and a support member; and an image carrier that is arranged to be rotatably supported by the support member so to move in a direction and directly or indirectly carries images; a plurality of rotating bodies (25, 33, 34) which are provided in the apparatus body, are rotationally driven independently of each other, and configured to apply forces to the image carrier unit, the forces being based on rotations of the rotating bodies (25, 33, 34); and a control unit that is configured to control driving states of the plurality of rotating bodies (25, 33, 34), characterized by a positioning part that is provided at the apparatus body and is configured to position the image carrier unit by being abutted against the support member; a pushing unit that is configured to push the support member in a normal direction opposite to the moving direction of the image carrier towards the positioning part; wherein the control unit is configured to control the rotating bodies (25, 33, 34) so that a resultant force of forces applied to the image carrier unit from the plurality of rotating bodies (25, 33, 34) is always applied in the normal direction where the support member is abutted against the positioning part, at least in one of the following periods: a period where the plurality of rotating bodies (25, 33, 34) moves to a normal rotation state from a stopped state, a period where the plurality of rotating bodies (25, 33, 34) move to the stopped state from the normal rotation state and a period where the plurality of rotating bodies (25, 33, 34) are made to be in the normal rotation state and image is carried on the image carrier.