A magnetic sensor capable of reducing noise caused by an interference magnetic field and capable of outputting a highly accurate signal in accordance with changes in a detected magnetic field includes a magnetic detection element, a first magnetic body having a first surface and a second surface, which is opposite to the first surface, and a second magnetic body positioned approximately in the center of the first magnetic body in the short direction on the first surface of the first magnetic body. The magnetic detection element is provided to be opposite to the second magnetic body with the first magnetic body interposed in between and positioned approximately in the center of the first magnetic body in the short direction. The magnetic sensing direction of the magnetic detection element is a direction approximately parallel to the short direction of the first magnetic body and the second magnetic body, and a width W1 of the first magnetic body is larger than a width W2 of the second magnetic body.