To provide a mounting structure of an opening frame material capable of improving workability of the opening frame material and recycling the opening frame material.

A mounting member 200 is fixed by using a machine screw 300 at a specified position of an opening edge part 450. Thereafter, an opening frame material 100 is set to that an engagement recessed part and an engagement protruded part are engaged with each other. A sash frame 700 is set, and a machine screw 800 is screwed in toward the opening frame material 100 from the sash frame 700. In this mounting structure, floating of the indoor side of the opening frame material 100 is prevented by an engagement relation with the mounting member 200, and lift up of the outdoor side of the opening frame material 100 is prevented by fixing it with the machine screw 800 conventionally.