To easily regulate hystersis applied to an accelerator operation force by providing a hysteresis regulating means between a rotary plate coupled to the accelerator pedal side, and a rotary shaft.

During the operation of the accelerator pedal, a turning shaft 17 is turned against return springs 19 and 20 through a rotary plate 24 and its turning angle is detected as an accelerator operation amount by a sensor part 18, A hysteresis generating part 21 applies frictional resistance force to rotation operation of a turning shaft 17 by using the press forces F in the axial direction of the return springs 19 and 20 and hysteresis is generated on an accelerator operation force. In a regulation work for the hysteresis, by pressing in the press-in cylinder part 26 of a turning plate 24 to the proper position of the turning shaft 17, the return springs 19 and 20 are axially compressed and deformed between a spring support part 24A and a casing 12 and the hysteresis is regulated easily.