Abstract: A measuring instrument that includes a tube 21 having a female thread 211 and a spindle 3 having a lead screw 31 screwing with the female thread 211 and capable of being advanced and retracted in an axial direction along with rotation around the axial center, and measures dimensions etc. of a workpiece according to displacement in an axial direction of the spindle 3 based on a rotation amount of the spindle 3. According to this measuring instrument, a pitch P of the lead screw 31 is twice as large or more than the difference between an external diameter R and a core diameter r thereof, and the difference between the external diameter R and the core diameter r is one-fifth or less of the external diameter R. Because of the lead screw 31 with the large pitch, the spindle 3 can be moved at high speed, thus enhancing operational performance of the measuring instrument.

Abstract: A measuring instrument that includes a tube 21 having a female thread 211 and a spindle 3 having a lead screw 31 screwing with the female thread 211 and capable of being advanced and retracted in an axial direction along with rotation around the axial center, and measures dimensions etc. of a workpiece according to displacement in an axial direction of the spindle 3 based on a rotation amount of the spindle 3. According to this measuring instrument, a pitch P of the lead screw 31 is twice as large or more than the difference between an external diameter R and a core diameter r thereof, and the difference between the external diameter R and the core diameter r is one-fifth or less of the external diameter R. Because of the lead screw 31 with the large pitch, the spindle 3 can be moved at high speed, thus enhancing operational performance of the measuring instrument.