To feed sheet stably without colliding against a vertical face of a sheet storage device by changing an oscillation amount of an oscillation means depending on a case where a first sheet storage device is mounted and a case where a second sheet storage device is mounted.

A pick up roller 3 oscillates centered on a feed roller shaft 4a of a feed roller 4 together with a roller holder 6 to start the sheet supply and feed operation. The pick up roller 3 starts to descend when pressure of the pick up roller 3 and pressure of a spring 311 which pushes up an envelope S2 are balanced well. It rises again and returns to its original position. During this time, the envelope S2 is fed out, is separated by the feed roller 4 and a retard roller 5, is supplied and fed, and is conveyed into an image formation part. Even if the pick up roller 3 attempts to descend furthermore, it does not descend any more because the roller holder 6 which becomes an oscillation means bumps against a projection 319 which becomes an oscillation regulation means.