A magnetoencephalograph comprising an oxide superconductor magnetic shielded vessel and a cryostat for cooling the magnetic shielded vessel, a multichannel SQUID and a cryostat for cooling the SQUID inserted together in the magnetic shielded vessel from one end of the magnetic shielded vessel, a magnetic-field detection unit situated in the vessel for detecting magnetic fields, and a coupling portion for coupling the SQUID and the magnetic-field detection unit with respect to the signals, and the SQUID and the magnetic-field detection unit being detachable. The magnetoencephalograph makes possible the detection of the very weak magnetic fields from the human brain and therewith reduction of the diameter of the opening of the magnetic shield vessel for inserting the SQUID. The reduction of the diameter of the SQUID opening in turn makes it possible to reduce the length of the magnetic shielded vessel, thereby preserving a high shielding effect of the magnetic shield vessel because of the L/D relationship. The magnetic shielded vessel is thus reduced to a practical size which is easy to handle and fabricatable at a low cost.
Magnetoencephalograph