According to one embodiment of the invention, a magnetic sensor includes a first element part. The first element part includes a first magnetic element, first and s second structures, a first magnetic member, and a second magnetic member. A direction from the first magnetic layer toward the first counter magnetic layer is along a first direction. The first structure includes a first side magnetic layer. The second structure includes a second side magnetic layer. The first magnetic element is between the first structure and the second structure in a second direction crossing the first direction. The first magnetic element is separated from the first side magnetic layer and the second side magnetic layer. A direction from the first side magnetic layer toward the first magnetic member is along the first direction. A direction from the second side magnetic layer toward the second magnetic member is along the first direction.