A fuel injection control device of an engine for controlling an injection amount of fuel, comprising: a fuel injection valve configured to inject a fuel according to a target pulse width into an intake passage; an intake flow rate detection unit arranged to detect a flow rate of an intake air supplied to the engine; an intake pressure detection unit arranged to detect an intake pressure in the intake passage; a fuel pressure detection unit arranged to detect a pressure of a fuel supplied to the fuel injection valve; a pressure control unit configured to control the fuel pressure according to an engine operation state; a request pulse width calculation unit configured to calculate a request pulse width on the basis of an intake flow rate detected by the intake flow rate detection unit, a fuel pressure detected by the fuel pressure detection unit, and a differential pressure between the fuel pressure and an intake pressure detected by the intake pressure detection unit; a correction coefficient calculation unit configured to calculate a first correction coefficient and a second correction coefficient for correcting the request pulse width on the basis of the differential pressure, wherein the first correction coefficient is set to decrease as the differential pressure becomes larger, and the second correction coefficient is set to increase as the differential pressure becomes larger; a post-correction request pulse width calculation unit configured to calculate a post-correction request pulse width through multiplying the request pulse width by the first correction coefficient, and adding the second correction coefficient to the multiplied value; and a target pulse width setting unit configured to set, in a region where the pulse width is smaller than a reference value, the target pulse width on the basis of the post-correction request pulse width, and in the other region, on the basis of the request pulse width. a fuel injection valve configured to inject a fuel according to a target pulse width into an intake passage; an intake flow rate detection unit arranged to detect a flow rate of an intake air supplied to the engine; an intake pressure detection unit arranged to detect an intake pressure in the intake passage; a fuel pressure detection unit arranged to detect a pressure of a fuel supplied to the fuel injection valve; a pressure control unit configured to control the fuel pressure according to an engine operation state; a request pulse width calculation unit configured to calculate a request pulse width on the basis of an intake flow rate detected by the intake flow rate detection unit, a fuel pressure detected by the fuel pressure detection unit, and a differential pressure between the fuel pressure and an intake pressure detected by the intake pressure detection unit; a correction coefficient calculation unit configured to calculate a first correction coefficient and a second correction coefficient for correcting the request pulse width on the basis of the differential pressure, wherein the first correction coefficient is set to decrease as the differential pressure becomes larger, and the second correction coefficient is set to increase as the differential pressure becomes larger; a post-correction request pulse width calculation unit configured to calculate a post-correction request pulse width through multiplying the request pulse width by the first correction coefficient, and adding the second correction coefficient to the multiplied value; and a target pulse width setting unit configured to set, in a region where the pulse width is smaller than a reference value, the target pulse width on the basis of the post-correction request pulse width, and in the other region, on the basis of the request pulse width.