PURPOSE: To carry out proper agricultural work adjustably adn easily according to its work content by providing an operation display means to display work conditions according to the work content of the agricultural machine.

CONSTITUTION: A main variable speed control mechanism 12 of hydraulic continuously variable speed type which becomes the drive part of an agricultural machine and changes the travel speed and cultivating speed, an auxiliary variable speed control mechanism 13 which is an auxiliary transmission gear in a transmission case, and a cultivating depth control mechanism 14 which is a lifting cylinder to lift a cultivator 3 controllably are provided in an agricultural machine. Also operation position display lamps 15, 16, and 17 as an operation display means to display by lighting the adjustment positions of main and auxiliary transmission levers 9 and 11 and a cultivating depth dial 10 at the operation positions on the name plates for the levers 9 and 11 and the dial 10 are provided, and the control mechanisms 12, 13, and 14 as well as the lamps 15, 16, and 17 are connected to a work control circuit 18 which is structured with a microcomputer. Because an operation display means to display the working conditions of a working machine is provided, an appropriate work for each work content can be made adjustably and easily to increase workability.