PURPOSE: To prevent deterioration of exhaust gas purification performance by shifting the upper limit value of a deceleration driving territory so that it is on the higher load side at the time of an engine cold state than at the time of engine hot state in a device making a mixed air air-fuel ratio lean at the time when a deceleration driving state of an internal combustion engine is detected.

CONSTITUTION: At the time of fuel injection control, in an ECU 23, a basic driving period is decided 51 in accordance with outputs of an air flow sensor 11 and a crank angle sensor 21. Additionally, while a feed-back time correction factor is set 53 in accordance with output of an O2 sensor 17, an air-fuel ratio correction factor is set 54. Thereafter, each of the correction factors is selected by changeover means 52A, 52B and used for drive control of an injector 8, but at this time, the changeover means 52A, 52B are changed over and controlled in accordance with a drive state by a changeover control means 57. At the time of selection of a setting means 54, a lean factor at the time of searching for the air-fuel ratio correction factor is decided in accordance with the detected result of a deceleration state, and the upper limit value of a deceleration driving territory is hifted so that it comes to be on the higher load side at the time of an engine cold state than at the time of an engine hot state.