To provide a waste paper binding auxiliary plate which is formed of a single plate, and allows anybody to easily bind a bundle of waste paper.

The waste paper binding auxiliary plate is made of a thermoplastic resin having flexibility and elasticity, and formed like a rectangular plate (11). The plate has an engaging portion (51) formed near an edge of each of long sides (21) and short sides (31) at a midpoint of each of the long sides and the short sides and provided with a binding string attaching/detaching means (41). Further the plate has at least one holding means (61) formed on each of the long sides and the short sides, for adjusting the length of the binding string.