A magnetic sensor capable of detecting a magnetic field with high sensitivity is provided. The magnetic sensor includes a bridge circuit having a plurality of magneto resistive effect elements connected with each other, and is capable of detecting a differential voltage between predetermined connecting points. The magneto resistive effect elements output resistance values which vary in accordance with a direction of a magnetic field to be input, and are arranged such that fixed magnetization directions of all magneto resistive effect elements are in the same direction. Further, a magnetic body which changes the direction of the magnetic field to be input to the magneto resistive effect elements is also provided in the vicinity of the bridge circuit.