A ventilation device comprising: a casing that includes an air-supply passage and an exhaust passage; an air-supply blower that is provided in the air-supply passage, and that blows outdoor air into the air-supply passage to form a supplied-air flow in a room; an exhaust blower that is provided in the exhaust passage, and that blows indoor air into the exhaust passage to form an exhaust-air flow to be discharged outside a room; a total heat exchanger that is located between the air-supply passage and the exhaust passage, and accommodated in the casing, and that performs total heat exchange between the supplied-air flow and the exhaust-air flow; an outside-air temperature sensor that measures a temperature of the outdoor air; an outside-air humidity sensor that measures a humidity of the outdoor air; an indoor humidity sensor that measures a humidity of the indoor air; a temperature regulating coil that is capable of changing a cooling capacity at multiple stages, and that dehumidifies the supplied-air flow after having undergone total heat exchange by the total heat exchanger; a target indoor-humidity storage unit that stores therein a target indoor humidity that is a target value of a humidity of the indoor air; and characterized in that the ventilation device further comprises: a control unit that decides a cooling capacity of the temperature regulating coil, such that a humidity of the supplied-air flow becomes the target indoor humidity, based on measurement values of the outside-air temperature sensor and the outside-air humidity sensor when the target indoor humidity is equal to or higher than an actual measurement value of a humidity of the indoor air measured by the indoor humidity sensor. a casing that includes an air-supply passage and an exhaust passage; an air-supply blower that is provided in the air-supply passage, and that blows outdoor air into the air-supply passage to form a supplied-air flow in a room; an exhaust blower that is provided in the exhaust passage, and that blows indoor air into the exhaust passage to form an exhaust-air flow to be discharged outside a room; a total heat exchanger that is located between the air-supply passage and the exhaust passage, and accommodated in the casing, and that performs total heat exchange between the supplied-air flow and the exhaust-air flow; an outside-air temperature sensor that measures a temperature of the outdoor air; an outside-air humidity sensor that measures a humidity of the outdoor air; an indoor humidity sensor that measures a humidity of the indoor air; a temperature regulating coil that is capable of changing a cooling capacity at multiple stages, and that dehumidifies the supplied-air flow after having undergone total heat exchange by the total heat exchanger; a target indoor-humidity storage unit that stores therein a target indoor humidity that is a target value of a humidity of the indoor air; and characterized in that the ventilation device further comprises: a control unit that decides a cooling capacity of the temperature regulating coil, such that a humidity of the supplied-air flow becomes the target indoor humidity, based on measurement values of the outside-air temperature sensor and the outside-air humidity sensor when the target indoor humidity is equal to or higher than an actual measurement value of a humidity of the indoor air measured by the indoor humidity sensor.