PURPOSE: To reduce a canister purge quantity at feedback control of air-fuel ratio by detecting open air temperature by an open air temperature detecting means, and controlling a purge time of a second control means by a purge time control means so that an evaporated fuel quantity remaining in a canister becomes larger as the temperature is lower.

CONSTITUTION: At starting an engine, a purge means (d) is operated by a first control means (e) so as to separate evaporated fuel in a canister (c) and feed it to an intake system. Then the purge means (d) is operated by a second control means (f) while controlling feedback of air-fuel ratio by an air-fuel ratio control means (b), and the evaporated fuel in the canister is fed to an intake system. At this time, own air temperature is detected by an open air temperature detecting means (g), and a purge time as an operating time of the second control means (f) is controlled by a purge time control means (h), so that the evaporated fuel quantity remaining in the canister (c) becomes larger as the temperature is lower. Consequently, degradation of operability, fuel consumption, and emission can be restrained.