The instrument cold sprays a solution sample at a low temperature and desolvates the sample. Under this condition, a mass analysis is performed. The instrument comprises a needle pipe (8) through which the solution sample is passed, a sheath tube (24) formed coaxially with the needle pipe (8) and passing a temperature-controlled nebulizing gas therethrough, the above-described desolvation block (3), means for cooling the block (15), means for heating the block (4), and a temperature sensor (5) for detecting the temperature of the block (3). The block (3) has a passage for charged liquid droplets of the solution sample cold sprayed from the tip of the needle pipe (8), and acts to remove the solvent from the charged liquid droplets flowing through the passage. A coldspray mass spectrometer is offered which has a desolvation block whose temperature can be easily controlled. In the instrument, condensation of water and electrical leakage are prevented for a long time. The instrument can perform measurements stably and is easy to handle.