A magnetic sensor includes a magnetization fixed layer, a magnetic field detecting layer, and an intermediate layer. The magnetization fixed layer is formed into a thin-film shape, and a magnetization direction of the magnetization fixed layer is fixed in a direction parallel to an in-plane direction. A magnetization direction of the magnetic field detecting layer changes depending on an external magnetic field. The intermediate layer is disposed between the magnetization fixed layer and the magnetic field detecting layer, and a resistance value of the intermediate layer changes depending on an angle between the magnetization direction of the magnetization fixed layer and the magnetization direction of the magnetic field detecting layer. A magnetization amount per unit area of the magnetic field detecting layer is less than 0.2 [memu/cm2].