To provide an attachment mounting base suitably applicable to HACCP support equipment.

The attachment mounting base comprises an outside member 13a and an inside member 13b arranged to sandwich a lower end of a side plate 2b of a conveyer frame 2 from outward and inward in the direction of board thickness of the side plate 2b, and a connecting member 13c connecting the inside member 13b with the outside member 13a. The outside member 13a is formed to attach an attachment 11 for mounting a guide rail 12. The inside member 13b is formed to stick a set screw 15 having a headless hexagon socket, being able to hold the side plate 2b between an end portion and the inner face of the inside member 13b by contacting the end with an inside face of the side plate 2b.