Magnetic sensor device

A magnetic sensor device comprising:

• at least one first-type magnetic sensor including at least one magnetic detection element and configured to generate a detection value corresponding to an external magnetic field;
• and
• a soft magnetic structure formed of a soft magnetic material, wherein
• the soft magnetic structure has such a magnetic property that a hysteresis loop of its magnetization with varying external magnetic field indicates a residual magnetization,
• the at least one first-type magnetic sensor and the soft magnetic structure are configured so that in the presence of the residual magnetization in the soft magnetic structure, a magnetic field based on the residual magnetization is applied to the at least one first-type magnetic sensor,
• the at least one first-type magnetic sensor, when used by itself, exhibits a first property such that, in a hysteresis loop of the detection value with varying external magnetic field, the detection value when the external magnetic field is zero is different from an ideal value by a first value other than zero,
• the at least one first-type magnetic sensor, when used in the magnetic sensor device, exhibits a second property such that, in the hysteresis loop of the detection value with varying external magnetic field, the detection value when the external magnetic field is zero is different from the ideal value by a second value, and
• the second value is smaller in absolute value than the first value.