PURPOSE: To perform easy control of a fuel direction and to improve a fuel consumption rate in a low load operation range, by installing means for heating an intake pipe and means for opening and closing a secondary air passage, and reducing the capacity formed between a fuel injection valve and the intake valve of a cylinder, to a half of the displacement of the cylinder.

CONSTITUTION: The fuel is injected in each intake pipe 7 through each fuel injection valve 4, and is dispersed at a wide injection angle by the revolving force of a secondary air flowing through a hot water valve 5 from a secondary air inlet 6. Since a wall, with which the sprayed fuel collides, is heated by hot water, the fuel is evaporated rapidly. Further, the volume of the air sucked by a piston 11 is set to a value being about two times as large as the capacity of the intake pipe 7 ranging from a fuel injection valve 10 to an intake valve 9, and thereby the injected fuel is all sucked in a combustion chamber 12 during an intake stroke.