PURPOSE: To provide an automatic measuring device of a cutting tool capable of automatically, easily and precisely measure dimension of the cutting tool.

CONSTITUTION: This device is furnished with a laser diameter measuring instrument 3 capable of measuring a diameter of a cutting tool 6 with no contact, a motor 2 for tool pot rotation to rotate a tool pot holding the cutting tool 6 and a motor 4 to move up and down the laser diameter measuring instrument 3 to move the laser diameter measuring instrument 3 vertically against the tool pot 1, and it automatically measures tool length, the tool diameter and tool roundness of the cutting tool 6.