To provide a crystallizer for shortening the time required for crystallization by starting the crystal growth process at the point of time when a predetermined amount of a concentrated liquid is stored in a concentrated liquid storage chamber having a small volume.

The crystallizer includes a crystallization container (14). The crystallization container (14) includes a first concentrated liquid storage chamber (58) and a second concentrated liquid storage chamber (59) which is located below the first concentrated liquid storage chamber (58) and has a volume smaller than the first concentrated liquid storage chamber (58).