PROBLEM TO BE SOLVED: To provide a displacement measuring device capable of performing displacement measurement that can realize high speed and high responsiveness and displacement measurements that have high accuracy and high resolution.
SOLUTION: The displacement measuring device includes a composite scale 2 for arranging a magnetic pattern 31 and a diffraction grating 32 in a measuring axis direction X, respectively; a magnetic detection part 11 for generating a first reproduction signal by detecting a magnetic field generated by the magnetic pattern 31 by being moved relative to the measuring axis direction X to the composite scale 2; a light source 12 for irradiating the diffraction grating 32 with light; and a detection head 3 having a light detecting part 13 generating a second reproduction signal, by detecting light diffracted by the diffraction grating 32. The device arranges the magnetic pattern 31 and the diffraction grating 32 so that the pitch of the first reproduction signal becomes larger than that of the second reproduction signal.
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