A magnetic sensor includes a first detection unit and a second detection unit. The first detection unit calculates a first detection angle which is a detected value of a first angle that a direction of an external magnetic field in a first position forms with respect to a first direction. The second detection unit calculates a second detection angle which is a detected value of a second angle that the direction of the external magnetic field in a second position forms with respect to a second direction. The first detection angle includes a first angular error. The second detection angle includes a second angular error. The first angular error and the second angular error differ in phase by an odd number of times ½ of the error period.