Magnetic encoder

A magnetic encoder including a magnetic scale unit and a position detection unit, the magnetic scale unit and the position detection unit moving relative to each other along a first direction, wherein

• the magnetic scale unit includes:
• a first magnetic field generation source and a second magnetic field generation source disposed side by side in the first direction and having magnetization directions opposite to each other;
• a magnetic body disposed with an interval away from the first magnetic field generation source and the second magnetic field generation source along a magnetization direction of the first magnetic field generation source and the second magnetic field generation source;
• and
• a base body to position the first magnetic field generation source, the second magnetic field generation source, and the magnetic body, the position detection unit includes:
• a magnetic detection element disposed in a region between the magnetic body and each of the first magnetic field generation source and the second magnetic field generation source with an interval between the magnetic detection element and each of the first magnetic field generation source, the second magnetic field generation source, and the magnetic body, and to output a change in magnetic field as an electric signal,
• the magnetic body has a length in the first direction, the length being a length corresponding to one wavelength of a wavelength determined on a basis of resolution of position detection of the magnetic scale unit in the first direction, and the magnetic body has a curved surface facing the first magnetic field generation source and the second magnetic field generation source, the magnetic body having an end portion in the first direction and positions corresponding to ¼ and ¾ of the wavelength from the end portion in the first direction, the curved surface being most convex at the positions corresponding to ¼ and ¾ of the wavelength, and
• the first magnetic field generation source is disposed at a position facing the position corresponding to ¼ of the wavelength, and the second magnetic field generation source is disposed at a position facing the position corresponding to ¾ of the wavelength.