PURPOSE: To improve the ground parallel lifting and lowering of a front working machine detachably installed to a front loader removable to a tractor and the workability of a small turn.

CONSTITUTION: A lift arm is composed of an original arm 2 and a front arm 4, which is attached pivotally to the original arm 2 and from which a front working machine such as a bucket 14 is mounted and dismantled freely, and a lift cylinder 18 lifting and lowering the front arm 4 is provided. A damp cylinder 15 driving the front working machine is connected to parallel links 13 using the original arm 2 as a component, a small turn is enabled by bending the front arm 4, and the ground parallel lifting and lowering of the front working machine is enabled by the parallel links 13.