A magnetic sensor device includes first and second surfaces, and first and second inclined surfaces, which are inclined with respect to the first surface; first through third magnetic sensor units for detecting magnetism in first through third axial directions; and a signal processing unit that performs signal processing on the basis of first through third sensor signals output from the first through third magnetic sensor units. The first axial direction is a direction orthogonal to the first surface, and the second and third axial directions are directions orthogonal to each other on the first surface. The first and second magnetic sensor units are provided on the second inclined surface, respectively. A corrected signal generation unit included in the signal processing unit generates first and second corrected signals, which are the first and second sensor signals corrected in accordance with the inclination angles of the first and second inclined surfaces.