PURPOSE: To carry out simultaneous operation of lifting, lowering and turning with one operating tool by enabling maintenance of a lifting or lowering operation state only for the set time with a lifting and lowering means when the operating tool is once operated in a state of stopped operation with an operation state sensing means.

CONSTITUTION: Turning means (4L), (4R), 5 and 7 and a controller (C) maintain a turning operation state during operation of an operating tool 8 from a stop position to a turning position and lifting and lowering means 2, 3 and 6 and the controller (C) maintain lifting or lowering operation state during the operation of the operating tool 8 from the stop position to a lifted or lowered position. An operating state sensing means (S) for sensing whether a ground working device 1 is in an operation state or not is provided. In the state of the stopped operation sensed with the aforementioned operation sensing means (S), the lifting and lowering means 2, 3 and 6 and the controller (C) are made to maintain the lifting or lowering operation state only for the set time if the opening tool 8 is once operated from the stopped position to the lifted or lowered position. As a result, simultaneous operation of lifting, lowering and turning can be carried out with one operating tool.