There is provided a biomagnetic field measurement apparatus capable of carrying out exact positioning work and highly sensitive signal detection. To bring a sensor surface close to a body surface while the sensor surface and the body surface are kept parallel, a cryostat is constructed so as to be capable of oscillating and expanding and contracting. A gantry is formed by three supports. A first support is a portal support that supports the whole of the gantry. A second support is supported on the first support, and is rotatable with a first direction being the axis. A third support is supported on the second support, and is movable in the axial direction of the cryostat as viewed from the second support. The cryostat is supported on the third support, and moves integrally with the third support.