Measurement instrument

A measuring instrument has a phase signal transmitter (400) that transmits, in accordance with a rotation of the spindle (300), a phase signal that differs corresponding to the rotation angle of the spindle (300), and an arithmetic processor (500) that arithmetically processes the phase signal to obtain the absolute position of the spindle. The phase signal transmitter transmits the phase signal at a predetermined pitch. Since the phase signal differs corresponding to the rotation angle of the spindle (300), a rotation angle of the spindle (300) is uniquely determined by the phase signal. Unlike an increment type measuring instrument, since there is no concern that the signal will be skip-read, the spindle (300) can be rotated at high speed, so that operational performance of the micrometer (100) can be improved. Further, since there is no concern that the signal will be skip-read, the phase signal can be minutely varied with respect to the rotation of the spindle (300).