A humidity control device (1) comprises: a processor (10) for dehumidifying air; a regenerator (30) for regenerating a hygroscopic liquid L used by the processor (10); a first hygroscopic-liquid pipe path (50) and a second hygroscopic-liquid pipe path (51) for circulating the hygroscopic liquid L between the processor (10) and the regenerator (30); and a heat pump (20) having an evaporator for cooling the hygroscopic liquid L to be used by the processor (10) and a condenser (22) for heating the hygroscopic liquid L flowing through the first hygroscopic-liquid pipe path (50). The regenerator (30) has: a first regeneration processing unit (31) and a second regeneration processing unit (34); a first tank (37) and a second tank (38) for containing the hygroscopic liquid L; and a heat source (44) for heating the hygroscopic liquid L to be supplied to the second regeneration processing unit (34). The hygroscopic liquid L in the first tank (37) is supplied to the first hygroscopic-liquid pipe path (50) to be supplied through the condenser (22) to the first regeneration processing unit (31) again. Consequently, high energy utilization efficiency can be maintained.