A fuel injection control device of an in-cylinder direct injection spark ignition-type internal combustion engine 1 in which fuel injection is carried out once or multiple times from an intake stroke to a compression stroke during homogeneous combustion, wherein a fuel injection timing at which a charging efficiency is improved in accordance with a pressure oscillation is calculated based on a frequency determined based on an in-cylinder volume of pressure oscillation generated in the cylinder in accordance with fuel injection, and one of the fuel injection(s) is carried out at the fuel injection timing.