PURPOSE: To provide a floor surface boring apparatus capable of automatically making two anchor bolt holes in the concrete floor surface.

CONSTITUTION: On a pedestral provided with pedestral fixing vacuum pads 3, 4, a pair of right and left boring drills 6, 7 and elevational driving means 9 are arranged and a guide frame 34 having openings 35a, 35b, through which the blade bodies 6a, 7a of both boring drills 6, 7 elevate, are permitted to approach the floor surface to thus be supported on the pedestral 1. On the opening circumferential part of the guide frame 34, positional marking parts 40a-40d, 42a, 42b are formed which fit at least in two parts on a transversely horizontal phantom line 39 connecting the axially equivalent positions of blade bodies of both boring drills 6, 7 and also at least in two parts on a longitudinally horizontal phantom line 41 passing through the middle between the axially equivalent positions of blade bodies and intersecting with respect to a transversely horizontal phantom line 39 and which can be aligned with cross lines L1, L2 drawn on the floor surface.