A binding unit includes a first pressing part that presses a recording material bundle to bind the recording material bundle, a second pressing part that faces the first pressing part, and a pushout part that pushes out the second pressing part toward the first pressing part by acting on the second pressing part using an upper shaft lever and by varying a distance from a start portion serving as a start point of pushout movement to the upper shaft lever. The start portion is formed integrally with a member at which the first pressing part is formed.