PURPOSE: To improve distribution property of mixture to each cylinder to provide a stable air-fuel ratio by providing a guide plate along an intake flow between a Venturi portion of an intake path and a case for supporting a fuel injection valve.

CONSTITUTION: The lower ends of guide plates 11a, 11b are formed to diverge to the right and left of an injection hole 10 so that an angle made by the lower end faces of both guide plates 11 is equalized to the maximum angle of fuel injection. Air guided from an air duct path to an intake path 1 is divided into four at a Venturi portion 6 by a stay 4a and the guide plates 11a, 11b perpendicular thereto to be conducted to the periphery of a throttle valve 5 so that the flow of intake air is put in order. Thus, the air is uniformly mixed with fuel sprayed from a fuel injection valve 2 to form a homogeneous mixture and improve distribution property to each cylinder.