To reduce power consumption of an electric heater and to realize deterioration prevention of a battery and enhancement of fuel consumption in a fuel carburetion device provided with the electric heater in an intake pipe and promoting fuel carburetion by the electric heater at cold of an engine.

In order to solve the above problem, an air passage for introducing air to the electric heater is provided and a fuel injection valve injects a fuel toward a plate-like member arranged in the air passage or a wall surface of the air passage. Further, as the other constitution for solving the problem, a plurality of heaters having independent power source circuit are provided and the number of the heaters energized according to the operation state of the internal combustion engine can be changed.