A controller for an internal combustion engine capable of performing a compression ignition operation. The internal combustion engine includes a combustion chamber, and a fuel injector for injecting fuel directly in the combustion chamber. The controller includes: an air pressure detecting unit configured to detect at least one of an air pressure and an exhaust air pressure; and a fuel injection control unit configured to actuate the fuel injector to control a fuel injection timing according to a detected result by the air pressure detecting unit. The fuel injection control unit puts the fuel injection timing forward as the detected result by the air pressure detecting unit is lowered.