There are provided: a pedal operation amount detection unit 12 that detects an operation amount s of the accelerator pedal 11; a speed ratio detection unit 14, 15 that detects a speed ratio e of an input shaft and an output shaft of the torque converter 2; a load pressure detection unit 16 that detects a load pressure P of the hydraulic pump 6; a speed stage detection unit 18 that detects a low speed stage of a transmission 3 capable of varying a speed stage between a low speed stage and a high speed stage; and a speed limiting unit 10 that limits a maximum speed of the engine 1 to a lower speed upon satisfaction of following speed limitation conditions: at least a pedal operation amount s is equal to or greater than a predetermined value s1, a speed ratio e is equal to or less than a predetermined value ea, a load pressure P is equal to or greater than a predetermined value Pa, and the low speed stage of the transmission has been detected.
