Magnetometer

A magnetometer which detects intensity of a magnetic field based on variation in fluorescence intensity, the magnetometer comprising:

• a diamond sensor including a plurality of nitrogen-vacancy centers;
• a diamond sensor case in which the diamond sensor is disposed;
• a reflection film reflecting excitation light and disposed on either a front surface or an inner surface of the diamond sensor case;
• an excitation light source which irradiates the diamond sensor in the diamond sensor case with the excitation light;
• and
• a fluorescence intensity detecting unit which detects the fluorescence intensity based on fluorescence from the diamond sensor case,
• wherein the diamond sensor case includes:
• a fluorescence output window through which the fluorescence occurring in the diamond sensor is output;
• and
• an excitation-light reception window through which the excitation light emitted by the excitation light source is received by the diamond sensor, and
• the fluorescence intensity detecting unit is disposed above a second main surface of the diamond sensor opposite to a first main surface of the diamond sensor, the first main surface being a magnetism measurement surface of the diamond sensor.