The plate thickness of an operation pedal having a hollow structure is maintained to be thin and the wearing and the buckling of a rotation connection portion on which a connection pin is arranged are suppressed. A reinforcing member (44) in which a pin insertion hole (52) is provided is arranged between parallel flat portions (32a) and (34a) of a pair of halved pieces (32, 34). A portion of the outer periphery edge of the reinforcing member (44) substantially corresponds to the side end edges (32e, 34e) of the parallel flat portions (32a, 34a) and is connected integrally with the side end edges (32e, 34e) by welding. Consequently, reactive force applied to the pair of parallel flat portions (32a, 34a) from a first connection pin (38) via the reinforcing member (44) is excellently dispersed, rigidity is improved, and the plate thicknesses of the halved pieces (32, 34) are maintained to be thin and the buckling caused by the reactive force is suppressed.