PURPOSE: To make easier the attaching and detaching operations of a loader by a method in which a control valve for a bucket and a lift arm and an operating lever for the lift arm are provided to the fitting frame of the front loader, and the operating lever of an operator room is connected with the control valve in a detachable manner.

CONSTITUTION: The lift arm 2 of a front loader 4 is attached to the fitting frame 3 of a tractor 1, and a control valve 5 for controlling the operation of a bucket 18 is provided to the lift arm 2. The control valve 5 has the operating lever 7 of the lift arm 2 and a coupling groove 23 is formed at the tip of spools 21 and 6 for the lift arm and the bucket. A coupler 10 receiving a wire 29 connected to the operating lever 9 to operate the bucket and lift arm in the operating seat is fitted into the coupling groove 23 of the control valve 5 in a detachable manner. The attaching and detaching operations of the front loader can thus be made by only one man at nearby positions.