PURPOSE: To provide a starting point checking method and its device, in which costs are lowered, by surely checking a starting point only by a signal from a mobile detector without providing any checking detector such as a limit switch for checking the starting point.

CONSTITUTION: In positioning of a moving member 3 at a starting point by means of a fluid cylinder 13, the fluid cylinder 13 is contracted/extended, and the specific change in a contracting/extending speed of the fluid cylinder 13 is performed because of cushioning effect of a cushion member 27 arranged in the contracting/extending end of the fluid cylinder 13, so that arrival of the moving member 3 at the starting point is checked by recognizing this change.