An impact hammer drill capable of performing drilling operation at a high speed with low noise and without requiring a large thrust. The drill includes a main shaft rotatable by an output shaft of a motor, and a spindle having an impact-receiving section and disposed over the main shaft slidably in its axial direction and rotatable together with the rotation of the main shaft. A piston is reciprocatingly slidably disposed over the main shaft for impacting against the impact-receiving section. A piston drive unit is disposed for driving the piston with a compressed fluid. A compressed fluid supplying unit is disposed for supplying the compressed fluid to the piston drive unit. A drill bit is attachable to the spindle. When performing drilling operation, the drill bit is imparted with a combined rotational motion and the reciprocal impact motion.