A fuel injection control apparatus of a four cycle engine having six cylinders (lla-f), comprising: a crank angle detection device for detecting crank angles of the four cycle engine; and a computation unit for computing a quantity of fuel injected in each stroke at a predetermined computation timing for each of the six cylinders (lla-f), characterized in that the computation unit comprises: a first computation device for computing a quantity of fuel, which is injected when a cylinder of the six cylinders is in a compression stroke of a four stroke cycle, at a first computation timing, when the cylinder of the six cylinders is in an intake stroke of the four stroke cycle; a second computation device for computing a quantity of fuel, which is injected in an intake stroke being one stroke before the compression stroke, at a second computation timing 240 degrees ahead of the crank angle of the first computation timing, when the cylinder of the six cylinders is in an exhaust stroke of the four stoke cycle; and a third computation device for computing a quantity of fuel, which is injected in an exhaust stroke being two strokes before the compression stroke, at a third computation timing 120 degrees ahead of the crank angle of the second computation timing, when the cylinder of the six cylinders is in an expansion stroke of the four stroke cycle. a crank angle detection device for detecting crank angles of the four cycle engine; and a computation unit for computing a quantity of fuel injected in each stroke at a predetermined computation timing for each of the six cylinders (lla-f), characterized in that the computation unit comprises: a first computation device for computing a quantity of fuel, which is injected when a cylinder of the six cylinders is in a compression stroke of a four stroke cycle, at a first computation timing, when the cylinder of the six cylinders is in an intake stroke of the four stroke cycle; a second computation device for computing a quantity of fuel, which is injected in an intake stroke being one stroke before the compression stroke, at a second computation timing 240 degrees ahead of the crank angle of the first computation timing, when the cylinder of the six cylinders is in an exhaust stroke of the four stoke cycle; and a third computation device for computing a quantity of fuel, which is injected in an exhaust stroke being two strokes before the compression stroke, at a third computation timing 120 degrees ahead of the crank angle of the second computation timing, when the cylinder of the six cylinders is in an expansion stroke of the four stroke cycle. a first computation device for computing a quantity of fuel, which is injected when a cylinder of the six cylinders is in a compression stroke of a four stroke cycle, at a first computation timing, when the cylinder of the six cylinders is in an intake stroke of the four stroke cycle; a second computation device for computing a quantity of fuel, which is injected in an intake stroke being one stroke before the compression stroke, at a second computation timing 240 degrees ahead of the crank angle of the first computation timing, when the cylinder of the six cylinders is in an exhaust stroke of the four stoke cycle; and a third computation device for computing a quantity of fuel, which is injected in an exhaust stroke being two strokes before the compression stroke, at a third computation timing 120 degrees ahead of the crank angle of the second computation timing, when the cylinder of the six cylinders is in an expansion stroke of the four stroke cycle.