To provide a fuel vapor adsorption device for preventing diffusion of fuel leaking to an intake system when an engine is stopped to atmospheric air in which intake resistance is not increased when the engine is actuated, and in which diffusion of fuel vaporized when the engine is stopped to be emitted to the atmospheric air is prevented.

In a throttle valve to regulate intake quantity in an internal combustion engine, adsorbent capable of adsorbing fuel is provided on a surface of the throttle valve on the internal combustion engine side (downstream side of an intake passage) when the throttle valve is totally closed. When the engine is stopped, fuel leaking from the injector to be vaporized is diffused. At this time, it also flows reversely to the upstream side of the intake passage. By the absorbent provided on the downstream side of the throttle valve disposed on the upstream side of the injector, reverse flow of evaporative fuel from a gap between the throttle valve and an inner surface of an intake pipe can be prohibited. When the engine is started, intake is not directly applied to the absorbent, thereby intake resistance is not generated.