In order to improve the sorption efficiency of the desiccant rotor, double ventilation rotor system has been proposed. In this system, at first the process air is dehumidified in the rotor. Next, the air becomes high relative humidity by cooling with an evaporator, and it is ventilated to the rotor again. In the first report, ventilation experiments of four types of air flow routes were investigated and it is clarified that each route has own characteristics on dehumidification. In this paper, the experiments of double ventilation rotor system of various flow routes were investigated with a refrigerator as a heat pump. Temperature and absolute humidity of the air at the entrance and exit of each zone were measured. Dehumidification amount of the rotor in single ventilation dehumidification system was equal to that in double ventilation dehumidification system. But recovered cold heat from evaporator in double ventilation dehumidification system was higher than that in single ventilation dehumidification system. With increasing the absolute humidity of inlet air, dehumidification amount of the rotor in each route and the absolute humidity of exit air increased. The COP of double ventilation dehumidification system was higher than that of single ventilation dehumidification system.