There are provided an accelerator grip, a biasing unit connected to the accelerator grip, the biasing unit biasing the accelerator grip to rotate in one circumferential direction, and a restricting unit restricting rotation of the accelerator grip against the biasing unit for placing the accelerator grip to a predetermined opening degree, wherein the restricting unit releases restriction of the accelerator grip when a predetermined operational force or more in one circumferential direction is applied to the accelerator grip so as to excessively rotate the accelerator grip in one circumferential direction beyond the predetermined opening degree.