PURPOSE: To improve a consumption rate of fuel enabling acceleration increase fuel to be supplied in the time of acceleration operation with no result of cost up by supplying a starting increase fuel by a starting fuel system as the acceleration increase fuel.

CONSTITUTION: A starting fuel system 32, supplying a starting increase of fuel in the time of starting, is provided. A solenoid valve 46 is provided interposing halfway a communication passage 44 connecting a storage chamber 36 to communicate with each branch starting fuel pipe 40. The starting increase of fuel, in order to supply it as an accelerating increase of fuel by the starting fuel system 32 in the time of acceleration operation, is controlled by a control circuit 60. In case of the opening of a throttle valve 26, detected by an opening sensor 56 and an engine speed sensor 58, being in a full degree further with an engine speed less than the preset value, an internal combustion engine is judged to be in acceleration operation, and the solenoid valve 46 is opened being actuated, supplying the accelerating increase of fuel by the starting fuel system 32 for only the preset time.