According to one embodiment, a PMV estimating device calculates a PMV value from an average room radiation temperature, room temperature, room humidity, room air velocity, an amount of cloth worn by a person in the room, and an amount of activity of the person in the room. The PMV estimating device includes: indoor solar radiation calculator; solar radiated article temperature estimator; and average radiation temperature estimator. The indoor solar radiation calculator calculates an amount of solar radiation entered into the room. The solar radiated article temperature estimator estimates a temperature of a solar radiated article receiving the solar radiation entered into the room, by using the amount of solar radiation entered into the room calculated by the indoor solar radiation calculator. The average radiation temperature estimator estimates the average room radiation temperature by using the temperature of the solar radiated article estimated by the solar radiated article temperature estimator.