In a backhoe that is a construction machine in which a swash plate angle of a variable capacity hydraulic pump driven by an engine is controlled based on a difference between an actual engine speed of the engine and a target engine speed calculated from an accelerator position, the engine is controlled through isochronous control when the actual engine speed of the engine is equal to or higher than a maximum torque engine speed with which a maximum torque of the engine is able to be output, and the engine is controlled through droop control when the actual engine speed of the engine is lower than the maximum torque engine speed with which the maximum torque of the engine is able to be output.