Mass spectroscope

A mass spectroscope comprising:

• a mass analysis device including a surface having metallic members capable of exciting plasmons when irradiated by laser light, the mass analysis device allowing an analyte to be attached to the surface;
• light radiating means for irradiating the surface of the mass analysis device with laser light to generate an energy thereon to ionize the analyte attached to the surface and desorb the analyte from the surface
• a polarization plate disposed on an optical axis of the laser light from the light radiating means;
• a polarization plate rotating unit that rotates the polarization plate about the optical axis of the laser light to change a polarization direction of the laser light so that the energy generated on the surface of the mass analysis device by the laser light is changed;
• and
• detecting means for calculating a plurality of mass spectrums of the analyte ionized and desorbed from the surface of the mass analysis device from of flight of the analyte for laser lights of different polarization directions due to a rotation of the polarization plate by the polarization plate rotating unit and detecting a mass of the analyte based on the calculated mass spectrums of the analyte.