The invention provides a variable speed control device of an operating vehicle, which can be used to reduce the impact of the speed changing from the high level to the low level and from the low level to the high level, and can be used to improve the speed changing feel. The variable speed control device (170) of the operating vehicle can be used for the multi-speed changing control of the operating vehicle (1), and is provided with a main transmission clutch (B),which is used for the speed changing at a plurality of speed-changing levels by using the rotating power; a Hi-Lo clutch (C), which is used to change the speed of the rotating power at the high level or the low level on the downstream side transmitted by the power of the main transmission clutch; a driver, which is used to adjust the pressing-connection state of various clutches; pressure sensors (171-176), which are used to measure the pressing-connection states of the clutches. During the speed changing by using the Hi-Lo clutch, the pressure of the speed changing target side of the Hi-Lo clutch can be maintained at the first pressure value, the speed of the main transmission clutch can be changed, and when the pressure of the speed-changing starting side of the main transmission clutch reaches the second pressure value, then the pressure of the speed changing target side of the Hi-Lo clutch can be increased.