A differential transformer type magnetic sensor (3, 3a, 3b, 3c), comprising: a first coil layer (21, 21a, 21b) including a detection coil formed of a planospiral first wire located on a plane and a first drive coil formed of a planospiral second wire running on the same plane as the first wire; a second coil layer (23, 23a, 23b) including a reference coil formed of a planospiral third wire located on a plane and a second drive coil formed of a planospiral fourth wire running on the same plane as the third wire; and a first insulating layer arranged between the first coil layer (21, 21a, 21b) and the second coil layer (23, 23a, 23b), characterized in that: the first wire and the second wire are parallel to each other and wound in a double spiral manner, the third wire and the fourth wire are parallel to each other and wound in a double spiral manner, the first drive coil and the second drive coil are electrically connected together so that a direction of drive current flowing in the first drive coil is the same as a direction of drive current flowing in the second drive coil, and the detection coil is electrically in differential connection to the reference coil so that a direction of induced current flowing in the detection coil is reverse to a direction of induced current flowing in the reference coil. a first coil layer (21, 21a, 21b) including a detection coil formed of a planospiral first wire located on a plane and a first drive coil formed of a planospiral second wire running on the same plane as the first wire; a second coil layer (23, 23a, 23b) including a reference coil formed of a planospiral third wire located on a plane and a second drive coil formed of a planospiral fourth wire running on the same plane as the third wire; and a first insulating layer arranged between the first coil layer (21, 21a, 21b) and the second coil layer (23, 23a, 23b), characterized in that: the first wire and the second wire are parallel to each other and wound in a double spiral manner, the third wire and the fourth wire are parallel to each other and wound in a double spiral manner, the first drive coil and the second drive coil are electrically connected together so that a direction of drive current flowing in the first drive coil is the same as a direction of drive current flowing in the second drive coil, and the detection coil is electrically in differential connection to the reference coil so that a direction of induced current flowing in the detection coil is reverse to a direction of induced current flowing in the reference coil. the first wire and the second wire are parallel to each other and wound in a double spiral manner, the third wire and the fourth wire are parallel to each other and wound in a double spiral manner, the first drive coil and the second drive coil are electrically connected together so that a direction of drive current flowing in the first drive coil is the same as a direction of drive current flowing in the second drive coil, and the detection coil is electrically in differential connection to the reference coil so that a direction of induced current flowing in the detection coil is reverse to a direction of induced current flowing in the reference coil.