To provide a position measurement method of a crankpin on a crankshaft grinder capable of measuring positions of a journal and the crankpin by restraining a measuring error to the minimum as well as to manufacture a position measurement device in a simple structure and at low cost.

Positional measurement of an end part of a journal and positional measurement of a crankpin are carried out by making a pair of probes 44A, 44B of a position measurement device 42 contact with a shoulder part 25 of a journal 21c and end parts of crankpins 22a-22d. It is possible to carry out these measurements at one point by rotationally moving a crankshaft 20 around the crankpins as its center at the time of theses measurements. Additionally, grinding positions and grinding width of the crankpins 22a-22d in the longitudinal direction of the crankshaft 20 with the end part of the journal as its standard are measured in accordance with the aforementioned measurement result.