A magnetic sensor includes a plurality of magnetoresistive element units. Each of the magnetoresistive element units includes a flat-surface-type first magnetoresistive element having a detection axis in a first direction and a flat-surface-type second magnetoresistive element having a detection axis in a second direction different from the first direction. The first magnetoresistive element and the second magnetoresistive element are arranged so as to face each other. The plurality of magnetoresistive element units are arrayed in a direction orthogonal to flat surfaces of the first magnetoresistive element and the second magnetoresistive element. The surfaces facing a measurement sample constitute a surface parallel to the direction in which the magnetoresistive element units are arrayed.