A tap 1 has a threaded portion 2 including a cutting blade 5 on an outer circumferential surface, a flute portion 3 that divides the threaded portion 2 in a circumferential direction, and a shank portion 4 formed continuously from the threaded portion 2 and the flute portion 3 along a central axis O. The flute portion 3 includes, in a cross-sectional view, a first flute 31 formed continuously from the cutting blade 5 of the threaded portion 2, a second flute 32 formed continuously from the first flute 31, and a ridge line portion 33 being a boundary between the first and second flutes 31, 32. A distance “e” from the central axis O to the ridge line portion 33 is longer than a distance d1 and a distance d2, respectively.

A tap 1 has a threaded portion 2 including a cutting blade 5 on an outer circumferential surface, a flute portion 3 that divides the threaded portion 2 in a circumferential direction, and a shank portion 4 formed continuously from the threaded portion 2 and the flute portion 3 along a central axis O. The flute portion 3 includes, in a cross-sectional view, a first flute 31 formed continuously from the cutting blade 5 of the threaded portion 2, a second flute 32 formed continuously from the first flute 31, and a ridge line portion 33 being a boundary between the first and second flutes 31, 32. A distance e from the central axis O to the ridge line portion 33 is longer than a distance d1 and a distance d2, respectively.