To prevent edge chipping when a through hole is formed in a work W of brittle material.

In a drilling tool for brittle material which drills a hole in a work formed of brittle material, a cutting blade part 15 having the outline that the rotational locus around the axis O is semi-spherical is formed on a tip of a columnar tool body 11 rotated around the axis O, a surface part in which at least the rotational locus of the cutting blade part 15 is semi-spherical is covered by a film 16 consisting of a diamond coating film, a diamond electro- deposited film, or a CBN electro-deposited film, or a surface part in which at least the rotational locus of the cutting blade part 15 is semi-spherical is formed of a diamond sintered body or a CBN sintered body.