Provided is an engine capable of performing post-injection control with a proper fuel injection amount. The engine (1) comprises an engine body (10) equipped with a turbocharger (7), an engine rotational speed sensor (21), an acceleration opening degree sensor (24), a boost sensor (23), a turbo sensor (22), and an ECU (100) for performing post-injection control. The ECU (100) recognizes the rotational speed of the engine, the supercharging pressure, the load on the engine, and the rotational speed of the supercharger, and so performs the post-injection control that the rotational speed of the supercharger becomes equal to the target rotational speed of the supercharger calculated in the ECU (100).