To provide a cutting edge length measuring method of a drill capable of recognizing a diameter of the drill with cutting edge length exceeding 9 mm using a conventionally used device (for example, a pressure foot having 15 mm of moving stroke and a tool diameter recognizing device having a measuring position 5 mm spaced from the upper surface).

In measuring a cutting edge length of the drill 4 having the cutting edge length longer than that of a typical drill, the drill 4 with a collet chuck 21 is located above a tool holding position H0, a drill holding position in machining. After finishing the measurement of the cutting edge length, the drill 4 is held again at the toll holding position H0 for machining.