A biomagnetic field map display apparatus for measuring a biomagnetic field generated by a biotest sample at positions arranged in rows and columns and displaying a magnetic field map obtained by processing the measured biomagnetic field. Data point values are predicted by the multiple functions. The module substrate of the first memory module has an aperture formed therein, the aperture being operable to provide an optical path for optical signals between the controller and an optical transmitterreceiver unit of the second memory module. Thereby, efficient up-conversion into blue light is made possible. The acknowledgement channel message may be one of a positive acknowledgement message and a negative acknowledgement message.