PURPOSE: To produce sherbet-like ice using a simple construction in an inexpensive manner by a method wherein an aqueous bromide solution of low concentration is used as heat storage water and then either unfreezable liquid or a refrigerant is passed around tubes in a shell.

CONSTITUTION: An in-tube ice making unit is constructed such that a shell-and- tube type ice making device having a plurality of fine tubes (coils) 2 in a shell 1 is applied and an aqueous bromide solution such as lithium bromide (LiBr) or the like of a low concentration is used as a heat storage material. The aqueous bromide solution is fed from an aqueous bromide solution inlet 4 into the tubes 2 of the shell 1, and either the unfreezable liquid or refrigerant is fed from an unfreezable liquid or refrigerant inlet 6 around the tubes 2, respectively, to cool the tubes 2, the aqueous bromide solution is kept still and then sherbet-like ice is produced in the tubes 2. The produced sherbet-like ice is pushed out of an aqueous bromide solution outlet 3 by passing the aqueous bromide solution from the aqueous bromide solution inlet 4.