Measurement device and measurement method

A measurement device comprising:

• a magnetic resonance member in which an electron spin quantum state changes in response to a measured field and in which an electron spin quantum operation can be performed by using a microwave;
• a high frequency magnetic field generator that performs the electron spin quantum operation of the magnetic resonance member by using the microwave;
• a light emitting device that emits excitation light to irradiate the magnetic resonance member;
• a fluorescence light receiving device that receives fluorescence emitted by the magnetic resonance member in response to the excitation light and generates a fluorescence sensor signal corresponding to an intensity of the fluorescence;
• and
• an arithmetic processing device that derives a measurement value based on the fluorescence sensor signal or a detection signal that is obtained from the fluorescence sensor signal,
• wherein a measurement value, which is measured when the measured field is applied to the magnetic resonance member, is defined as a main measurement value,
• a measurement value, which is measured when the measured field is not applied to the magnetic resonance member and before the main measurement value is measured, is defined as a preceding measurement value,
• a measurement value, which is measured when the measured field is not applied to the magnetic resonance member and after the main measurement value is measured, is defined as a succeeding measurement value, and
• the arithmetic processing device respectively subtracts the preceding measurement value and the succeeding measurement value from the main measurement value at a predetermined ratio to derive the measurement value of the measured field.