Abstract: Provided is a control unit (1) for an internal combustion engine (10) including a direct injector (11) directly injecting fuel into a cylinder (20) and a port injector (12) injecting fuel into an intake port (17). The control unit (1) includes an injection volume calculator (5) to calculate a volume of the fuel injected from the direct injector (11), a port injection controller (2) to control a volume of the fuel injected from the port injector (12), an overlap period controller (4) to control an overlap period during which both an intake valve (27) and an exhaust valve (28) are open, and a changer (6) to vary both the volume of the port injection from the port injector (12) and the overlap period based on the volume of the direct injection.