PURPOSE: To simply discriminate whether a lengthy sheet is set on a paper sheet feed tray at present or not.

CONSTITUTION: A paper feed tray 20 is provided with a tray main body 30, and an extension tray 31 rotationally movably connected to the tray main body 30. The tray main body 30 is formed with a receiving recessed part 30 to conform to the external form of the extension tray 31. The extension tray 31 is movable to a receiving position on which the extension tray 31 is received in the receiving recessed part 30b so as to narrow the sheet placing face 20a, or an extended position on which the extension tray is opened to spread the sheet placing face 20a. Further, a tray position detecting sensor 33 to detect the extension tray being in the extended position is provided in the receiving recessed part 30b. When a lengthy sheet S is set on the paper feed tray 20, the extension tray 31 is placed in its extended position, and the position is detected by means of the tray position detecting sensor 33.