PURPOSE: To make it possible to bore an exact hole without applying tipping moment to a spindle stock by a structure wherein guide members, onto which the spindle stock is supported, and a drill are held on the same plane.

CONSTITUTION: A horizontal pair of guide rods 2 and 2, along which a spindle stock 3 is shiftably seated, are laid in the direction of motion on a main body frame 1. A rack 4, which is laid on one side of the main body frame 1, engages with a pinion 6, which is driven by a motor 5 for shifting provided on the spindle stock 3. The spindle stock 3 straddlingly fits to a pair of the guide rods 2 and 2, is shiftable along the guide rods 2, lies on the same plane as a pair of guide rods 2 and 2 and holes a drill with a chuck 7 on the center lines of both the guide rods. By advancing the spindle stock 3 under the state that the drill 8 is rotatingly driven, the boring is done to a workpiece. At this time, the force acting to the spindle stock does not act as the tipping moment to the spindle stock, since said force acts in the same plane as the guide members of the spindle stock.