To provide a crystallizer capable of reliably condensing steam discharged from a crystallizer by sufficiently cooling it and suitably maintaining a pressure in the crystallizer.

The crystallizer 100 includes: a crystallization can 110; an agitator 112; a heat exchanger 114 in the crystallization can arranged inside the crystallizer; a heat pump 120 including a heat recovery coil 122, a compressor 124, a heat supply coil 126, and an expansion means 128; a steam generator 130 in which the heat supply coil is arranged; a heating medium supply path 136a; and a condenser 140. The condenser includes the heat recovery coil arranged at a downstream side of a steam supply port 140a and a cooling means 142 arranged at the downstream side thereof and causing a cooling water to be in contact with the steam. The steam supplied to the condenser is condensed by the heat exchange with a refrigerant circulating in the heat recovery coil and the contact with the cooling water supplied to the cooling means.