To provide a construction machine that can prevent a reaction force from working horizontally from a leader onto a front bracket and a support arm, and can execute easily fine adjustment for positions of pile centers.

In a construction machine that is equipped with a self-propelled vehicle 14 having a front bracket 10 at its front and a back stay 12 at its rear so that it can be risen and fallen and a leader 20 held at its lower part with the front bracket 10 and held at its upper part with the back stay 12 while being capable of rising and falling by means of expansion and contraction of the back stay 12, the self-propelled vehicle 14 is equipped with oil hydraulic cylinders 28, 28 that support the leader 20 at positions lower than where the leader 20 is supported with the front bracket 10, and the leader 20 is supported respectively with the front bracket 10, the back stay 12 and the oil hydraulic cylinders 28, 28.