Magnetic encoder

A magnetic encoder is provided, in which a large output voltage (a large amplitude) is obtained so that the magnetic encoder can have a strong resistance to external noise and so that malfunction can be prevented.Each of first to fourth magnetoresistance elements A, A, A, and A has at least a pinned layer, and a free layer in which an internal magnetization direction changes in accordance with external magnetic fields emitted by a magnetic body . A magnetization direction α of the pinned layer is set to be in a first direction (a direction Z) that is parallel to an outer peripheral side surface A and that is perpendicular to rotation directions ra-ra, or is set to be in a second direction (a direction Z) that is opposite to the first direction. Additionally, an initial magnetization direction β of the free layer is set to be in the first direction (the direction Z) or the second direction (the direction Z). When a pitch of N and S poles adjacent to one another in the rotation direction is denoted by λ, a pitch of the magnetoresistance elements A, A, A, and A is set to a pitch of λ/2.