PURPOSE: To adjust a step-on feeling of an accelerator pedal in accordance with an operating condition of an engine.

CONSTITUTION: A throttle valve 5 provided in an intake pipe 2 of an engine 1 is driven to open/close by a stepping motor 6. An accelerator opening sensor 10 for detecting an accelerator operating amount is provided in an accelerator pedal 9. A water temperature sensor 32 for detecting a temperature of circulative cooling water is provided in the engine 1, and a shift position sensor 33a for detecting a shift position is provided in a shift lever device 33. In a CPU23, a play amount (dead band width) of the accelerator pedal 9 is set in accordance with a temperature of cooling water by the water temperature sensor 32 and a shift position by the shift position sensor 33a. The CPU23 controls the stepping motor 6 in order to obtain a throttle opening corresponding to the accelerator operating amount by the accelerator opening sensor 10 by using this play amount.