PURPOSE: To prevent variation in air-fuel ratio at the time of shifting from a high load to a low load when controlling an evaporated fuel in accordance with an operating condition and feeding the fuel into an engine by reducing the rate of change in the feeding quantity of the evaporated fuel at the time of shifting from a high load to a low load as compared to the time of shifting from a low load to a high load.

CONSTITUTION: Detected signals from an O2 sensor 9a in addition to an engine speed and an intake air quantity are inputted into a control unit 17, to control a duty solenoid valve 16 provided in an evaporated fuel passage connecting a canister 15 and an intake passage 8 so as to prevent an evaporated fuel from being fed from the canister 15 into an engine at the time of idling, etc. The control unit 17 sets the correction factor of the feeding characteristic of the evaporated fuel to be small when the load change of the engine is shifted from a high load to a low load as compared to the time of shifting from a low load to a high load.