PURPOSE: To simplify the construction of a cassette, reduce its size and weight and facilitate its handling, by making it possible that the position of at least one of a pair of cassette reception members provided on the frame of a paper feed section and having cassette reception grooves facing each other is changed in the direction of the width of the cassette.

CONSTITUTION: When a paper feed cassette 3 is to be set in a paper feed section 2, the paer feed cassette is chosen depending on the size of a copy and the positions of both reception members 4, 5 are adjusted depending on the size. At that time, the operating member 71 of a locking means is turned counterclockwise to push down a clamping plate 7 to separate an elastic member 76 from the bottom of a frame 21 to unlock the reception member 4. The member 4 is then moved to a position corresponding to the size of the cassette 3. The operating member 71 is turned clockwise to pull up the clamping plate 7 to bring the elastic member 76 into pressure contact with the bottom of the frame 21 to lock the reception member 4 in a prescribed position. Since such paper feed cassettes are exclusively used for sizes of copies, respectively, an adjusting partition plate or the like does not need to be provided in each cassette. This results in simplifying the construction of each cassette, reducing its size and weight and facilitating its handling.