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 A1, A2, A3, and A4 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 11. A magnetization direction α of the pinned layer is set to be in a first direction (a direction Z2) that is parallel to an outer peripheral side surface 11A and that is perpendicular to rotation directions ra1-ra2, or is set to be in a second direction (a direction Z1) 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 Z2) or the second direction (the direction Z1). 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 A1, A2, A3, and A4 is set to a pitch of λ/2.