A high-frequency magnetic field generator 2 applies microwave to a magnetic resonance member 1. A magnet 3 applies a static magnetic field to the magnetic resonance member 1. An irradiating device 12 irradiates the magnetic resonance member 1 with incident light of a specific wavelength. An FT 4 senses a measurement target magnetic field using a primary coil 4a and applies an application magnetic field corresponding to the sensed measurement target magnetic field to the magnetic resonance member 1 using a secondary coil 4b. A pillar-shaped light guide member 41 guides the incident light to the magnetic resonance member 1, and a pillar-shaped light guide member 42 guides fluorescence that the magnetic resonance member 1 emits from the magnetic resonance member 1. Further, the magnetic resonance member 1 is arranged between an end surface of the light guide member 41 and an end surface of the light guide member 42 in a hollow part of the secondary coil 4b of the FT 4 and in a hollow part of the aforementioned magnet 3.