Patent ID: 7273124

Claim:
A prime mover control device of a construction machine that includes: a hydraulic pump driven by a prime mover; a hydraulic traveling motor driven with pressure oil output from the hydraulic pump; and a control valve that controls a flow of the pressure oil from the hydraulic pump to the hydraulic motor in response to an operation of an operating member, comprising: a deceleration detection device that detects a deceleration operation at the operating member; a rotation speed detection device that detects a rotation speed of the hydraulic motor; and a prime mover rotation speed control device that executes speed reduction control of the rotation speed of the prime mover based upon detection results provided by the rotation speed detection device if the deceleration operation is detected by the deceleration detection device and that controls the rotation speed of the prime mover in correspondence to an operation of the operating member which is detected to be other than the deceleration operation.