An image forming apparatus comprising: a toner case; and an attachment part to which the toner case is detachably attached, wherein the toner case includes: a case main body storing a toner; a rotator (22, 23) stored in the case main body and rotating around a rotation axis (X, Y); a transmitter arranged outside the case main body and transmitting rotation to the rotator (22, 23); and a moving mechanism which is configured to move the transmitter between a first position and a second position which is arranged further away from the first position in a rotation axis direction of the rotator (22, 23), pointing to an outside of the case main body, wherein the moving mechanism includes a holder holding the transmitter, the attachment part includes a restriction part which comes into contact with the holder to restrict rotation of the holder, and the apparatus is adapted so that as the case main body rotates with respect to the holder in a state where the restriction part comes into contact with the holder, the transmitter moves from the first position to the second position, the holder is configured to move between a first holding position where the holder holds the transmitter in the first position and a second holding position where the holder holds the transmitter in the second position, characterized in that the moving mechanism further includes a biasing member which biases the holder to the second holding position, the apparatus is adapted so that, as the toner case is attached to the attachment part, the restriction part comes into contact with the holder and the holder moves from the second holding position to the first holding position against biasing force of the biasing member, and as the case main body rotates with respect to the holder in a state where the toner case is attached to the attachment part, the holder moves from the first holding position to the second holding position by the biasing force of the biasing member. a toner case; and an attachment part to which the toner case is detachably attached, wherein the toner case includes: a case main body storing a toner; a rotator (22, 23) stored in the case main body and rotating around a rotation axis (X, Y); a transmitter arranged outside the case main body and transmitting rotation to the rotator (22, 23); and a moving mechanism which is configured to move the transmitter between a first position and a second position which is arranged further away from the first position in a rotation axis direction of the rotator (22, 23), pointing to an outside of the case main body, wherein the moving mechanism includes a holder holding the transmitter, the attachment part includes a restriction part which comes into contact with the holder to restrict rotation of the holder, and the apparatus is adapted so that as the case main body rotates with respect to the holder in a state where the restriction part comes into contact with the holder, the transmitter moves from the first position to the second position, the holder is configured to move between a first holding position where the holder holds the transmitter in the first position and a second holding position where the holder holds the transmitter in the second position, characterized in that the moving mechanism further includes a biasing member which biases the holder to the second holding position, the apparatus is adapted so that, as the toner case is attached to the attachment part, the restriction part comes into contact with the holder and the holder moves from the second holding position to the first holding position against biasing force of the biasing member, and as the case main body rotates with respect to the holder in a state where the toner case is attached to the attachment part, the holder moves from the first holding position to the second holding position by the biasing force of the biasing member. a case main body storing a toner; a rotator (22, 23) stored in the case main body and rotating around a rotation axis (X, Y); a transmitter arranged outside the case main body and transmitting rotation to the rotator (22, 23); and a moving mechanism which is configured to move the transmitter between a first position and a second position which is arranged further away from the first position in a rotation axis direction of the rotator (22, 23), pointing to an outside of the case main body, wherein the moving mechanism includes a holder holding the transmitter, the attachment part includes a restriction part which comes into contact with the holder to restrict rotation of the holder, and the apparatus is adapted so that as the case main body rotates with respect to the holder in a state where the restriction part comes into contact with the holder, the transmitter moves from the first position to the second position, the holder is configured to move between a first holding position where the holder holds the transmitter in the first position and a second holding position where the holder holds the transmitter in the second position, characterized in that the moving mechanism further includes a biasing member which biases the holder to the second holding position, the apparatus is adapted so that, as the toner case is attached to the attachment part, the restriction part comes into contact with the holder and the holder moves from the second holding position to the first holding position against biasing force of the biasing member, and as the case main body rotates with respect to the holder in a state where the toner case is attached to the attachment part, the holder moves from the first holding position to the second holding position by the biasing force of the biasing member.