To perform high-precise pitch feeding with backlash hardly occurring.

A conveyance mechanism comprises a clamp mechanism 3 to hold a steel plate 6: a base part 7 having the clamp mechanism 3; and a conveyance mechanism to convey the steel plate 6 in a held state move the base part 7. The conveyance mechanism comprises a male screw part 1 extended in the conveyance direction of the steel plate 6; and a female screw part 2 arranged at the base part 7 and rotatably threadedly engaged with the male screw part 1 and having ball screw structure.