A magnetic sensor device is connectable to a data processing device and is a circuitry physically separate from the data processing device. In the magnetic sensor device, a detection unit detects magnetic field and outputs analog magnetic data representing the detected magnetic field. A conversion unit converts the analog magnetic data into digital magnetic data. A buffer memory has a capacity capable of storing a statistical population formed of a given number of the digital magnetic data. A control unit responds to a first trigger for operating the detection unit to successively output the analog magnetic data, then successively receives the digital magnetic data from the conversion unit in correspondence to the analog magnetic data, and accumulates the received digital magnetic data in the buffer memory to thereby form the statistical population. The control unit further responds to a second trigger for providing the data processing device with the statistical population accumulated in the buffer memory and formed of the given number of the digital magnetic data.