A hybrid-type construction machine includes a controller configured to control a revolution speed of an engine; a hydraulic pump configured to be driven by the engine; a motor generator configured to assist the engine; and a hydraulic circuit configured to supply an operating oil discharged from the hydraulic pump to a hydraulic load, wherein when the controller determines that the hydraulic circuit is in an excessive output state, the controller controls the revolution speed of the engine so as to be lower than an ordinary revolution speed of the engine while controlling the motor generator to generate electricity.