To control an engine to a desired A/F characteristic at acceleration/ deceleration time, provide a good operation following ability, and keep exhaust gas in a clean condition, by specifying a cylinder in a given crank angle range when acceleration or deceleration is detected, and sequentially correcting fuel injection amount from the cylinder.

A setting means 205 sets fuel injection amount based on output signals from a rotation speed detecting means 201 and a load detecting means 202. An air-fuel ratio detecting means 200 detects air-fuel ratio (oxygen concentration) after combustion, an air-fuel ratio control means 206, based on the detection signals, derives fuel injection time and fuel injection timing so that the air-fuel ratio equals to a theoretical air-fuel ratio, and a fuel injection valve 13 is feed-back controlled. When acceleration or deceleration is judged by a judging means 209 based on output from the load detecting means 202, based on the outputs from an crank angle detecting means 203 and a specific cylinder judging means 204, a specific means 210 specifies a cylinder whose fuel is to be corrected, and sequentially makes fuel injection amount corrected from the specified cylinder.