Biomagnetic measurement apparatus

A biomagnetic measurement apparatus having functions to detect the release of a magnetic field lock in a SQUID fluxmeter operation circuit due to the influence of a much greater noise level than that of a biomagnetic signal, to notify an operator of the release of the magnetic field lock, and to automatically or manually revert to a state for allowing magnetic measurement. The release of the magnetic field lock occurs when an integrator of the fluxmeter operation circuit is saturated. Thus, a high pass filter is provided at a subsequent stage of the integrator, and a function is provided to judge that the integrator is in a saturated state when the noise level of the output after passing through the high pass filter is lower than a pre-set threshold. The biomagnetic measurement apparatus can detect a saturated state of the integrator, which is a cause for the release of the magnetic field lock of the SQUID fluxmeter operation circuit, and thereby when the loading of measured data is conducted in an appropriate operation range of a magnetic sensor, or even when a part of the loaded measured data is data outside an operation range of the magnetic sensor, it is possible to deal with the data so as to properly analyze it.