PURPOSE: To reduce running cost and suppress wasteful use of washing water by increasing and decreasing the speed of a washing machine engine automatically according to the opening and closing of a washing jet nozzle.

CONSTITUTION: An automatic speed increasing and decreasing device for washing machine engine is formed with a fluid pressure cylinder 19, a connecting body 20 to interlockingly connect a rod 25 of the fluid pressure cylinder 19 to a speed control lever 9 of an engine of a washing machine, and a pilot hose 21 of which one end is connected to a high pressure pump 11 and the other end is connected to the fluid pressure cylinder 19, and which leads pressure water from the high pressure pump 11 to the fluid pressure cylinder 19. Also the fluid pressure cylinder 19 is operated by pressure water with a pressure over a specified level which is led through the pilot hose 21 when a washing jet nozzle is closed so as to rotatably operate the speed control lever 9 at a low speed rotating position. Then, when the washing jet nozzle is opened, it is operated in the direction reverse to that operation so as to control the speed control lever 9 drivingly so that it is operated lotatably at a high speed rotating position.