A method of sequentially injecting fuel into the cylinders of a multi cylinder internal combustion engine in predetermined sequence in synchronism with generation of pulses of a trigger signal, wherein the quantity of fuel to be injected into each cylinder is set to a value appropriate to an operating condition of the engine then detected, upon generation of each pulse of the same signal, and the fuel supply to each cylinder is interrupted when the engine is decelerating in a predetermined operating condition. When it is determined that a predetermined condition for terminating the interruption of the fuel supply to the engine is satisfied, one of the above sequential injections is effected into a cylinder corresponding to a present pulse of the trigger signal at the time of generation of a present pulse of the same signal, and simultaneously an additional injection is effected into another cylinder corresponding to a preceding pulse of the trigger signal. Preferably, the quantity of fuel to be injected by the additional injection is set to be a value substantially equal to that by the above one of the sequential injections.