PURPOSE: To prevent the dislocation of a boring position caused by the vibration of a boring machine with a level block.

CONSTITUTION: The boring machine is provided with a vice 1 for grasping a material (a) to be worked, a level block 3 to be fitted to the material (a) to be worked movably attached to the vice 1 via a screw 2, a boring device 4 secured to the level block 3, and a rotational-operating handle 5 for the forwarding screw 2 fixed to the vice 1. The rotational-operating handle 5 is disposed in the proximity of the boring device 4 in the form of its handle shaft 5a extended upward. The handle shaft 5a of the rotational-operating handle 5 is attached with a worm, and the forwarding screw 2 is also attached with a worm wheel to be engaged with the worm.