To provide an intake device for an internal combustion engine, capable of easily and positively achieving the narrowing of a gap between a throttle valve and a throttle body, the reduction of an amount of deposit, and cleaning without causing any problems even when an oil and water repellent treatment is applied to both of the throttle valve and the throttle body.

In the intake device, after applying a solid lubricant layer 45 for reducing the gap S1 between the throttle valve 17 and the throttle body 16 between an outer circumference end face of the throttle valve 17 and an inner face of the throttle body 16, a monomolecular film (a coating film) 46 of a perfluoropolyether compound having a functional group in an end is formed. The solid lubricant layer 45 is formed on the periphery of a throttle shaft 40 so as to block the intake passage side end face of a gap S2 between the throttle shaft 40 and an insertion hole 42 of the inner face of the throttle body 16.