A paper feeding apparatus includes a cassette main body that stacks a paper therein, a sidewall that moves in a width direction of the cassette main body, an end wall that moves in a longitudinal direction of the cassette main body, a first movable member that is connected at one end to the sidewall and rotates around a shaft axially fixed to the cassette main body in connection with the sidewall, a second movable member that is connected at one end to the end wall and rotates around a shaft axially fixed to the cassette main body in connection with the end wall, a first detection unit that has a plurality of detection members and detects the size of the paper in the width direction, and a second detection unit that has a plurality of detection members and detects the size of the paper in the longitudinal direction.