To provide a guide plate device in a hopper of a waste paper binding apparatus by which waste paper can be supplied in the hopper without stopping a conveyor to enhance a binding efficiency.

In this guide plate device, a guide plate composed of a tiltable guide upper part and a vertical guide lower part are arranged along a vertical inner wall surface at the lower end part of the hopper. Then, the waste paper are guided by changing the inclination of the tiltable guide upper part corresponding to the type of the waste paper, and a connecting hole communicated with a press case from lower end part of the hopper is expanded/reduced by changing the interval between the tilable vertical lower part and the corresponding inner wall surface to increase/decrease the vertical guide storage amount at the lower part of the hopper. In this way, magazines and advertizing paper sheets heavy in mass can smoothly pass through the guide plate device to be fed to the press case without any resistance.