PURPOSE: To maintain constant paper feeding pressure regardless of the size of paper used, regarding a paper feeding device.

CONSTITUTION: A paper feeding cassette 20 is equipped with a bottom plate expansion means 33, a bottom plate support means 29, an interlocking means 47 and a bottom plate energizing means 39. The bottom plate expansion means 33 forms a bottom plate 35 out of a lower bottom plate 36, an intermediate bottom plate 37 and an upper bottom plate 38, and enables the bottom plate 35 to contract and expand approximately to the same length of a loaded paper sheet via the engagement of slits 36c and 37c with guide pieces 37b and 38a. The bottom plate support means 29 enables the bottom plate 35 to be mounted on a cassette case 20A in such a way as capable of free vertical turn like a seesaw about a lengthwise intermediate position as a support point. The interlocking means 47, interlocked with a contracting and expanding motion with the means 33, enables the support point of the bottom plate 35 to move toward the intermediate position. Furthermore, the bottom plate energization means 39 energizes and turns the bottom plate 35 at all times with an approximately constant energizing force, thereby enabling the forward end thereof to be lifted.