PURPOSE: To simplify installation work by performing power source wiring without using exclusive wiring in a body of car when a main body of air cleaner is intalled in a rear room of a car.

CONSTITUTION: There are provided a pressure sensor 10, which is provided in a fuel feed pipe 7 for sending fuel from a fuel tank 6 of automobile to an engine 8, for detecting the flow of fuel in the pipe 7, a fuel feed detecting device 11 for detecting feed of fuel based on the output signals of the sensor 10, and a power source control circuit 13 provided in a main body 12 of an air cleaner, so that actions of the circuit 13 are controlled based on the output of the device 11 to actuate the main body 12 only when an engine key is inserted to actuate the engine 8.