To carry out the control of room temperature so that the temperature is comfortable to a sleeper in regard to the temperature control of a period set by a sleep timer.

In a control part, when the sleep timer is started, a target temperature is set at +0.5C of a set temperature, and activity amount calculation is started at the same time. After 30 minutes, since an activity amount of the past 30 minutes is "small" or smaller, in the next 30 minutes, control is carried out by increasing a target temperature by 0.5C. After another 30 minutes, since the activity amount is "small" or larger, the target temperature is lowered by 0.5C, and after 30 minutes, since the activity amount is "small" or smaller, the target temperature is increased by 0.5C, and operation is carried out at the target temperature. After the next 30 minutes, since the activity amount is "large" or larger, the target temperature is lowered by 1.0C, and after 30 minutes, since the activity amount is "small" or smaller, the target temperature is increased by 0.5C, and operation is carried out in the target temperature. Since the activity amount is "small" or smaller thereafter, the target temperature is sequentially increased by 0.5C every 30 minutes, and operation is carried out in the target temperature.