The invention relates to a control method for an air purifying device, operating an actuator, and using a control part to adjust the distance between a sealing plate and a through hole, between a first sealing member and an air intake hole, and between a communication hole connecting a casing and the air intake hole The temperature of the air entering the through hole and the dust concentration contained in the air are detected by each air temperature sensor and dust concentration sensor. The control unit calculates the detected signal value, and then adjusts the sealing plate and the through hole. The distance between the holes, the distance between the first sealing member and the air intake hole, and the distance between the communication hole connecting the casing and the air intake hole, thereby adjusting the air supply amount of the outside air entering the room. According to the present invention, in order to correspond to the calculated value of the air temperature detected by the air temperature sensor and the calculated value of the dust concentration detected by the dust concentration sensor, the distance between the sealing plate and the through hole is adjusted, thereby adjusting the amount of outside air entering the room, In addition, the distance between the communication hole connecting the housing and the air intake hole is adjusted in inverse proportion to the distance between the sealing plate and the through hole, and then the distance between the communication hole and the air intake hole is adjusted inversely proportional to the increase or decrease in the supply amount of the outside air entering the air purifier. Or increase the air supply volume of the air entering the air purifier, while maintaining the indoor temperature and reducing the pollution degree, especially, the control part calculates the signal value received from the air temperature sensor and the dust concentration sensor, and then has the ability to automatically adjust the sealing plate and Advantages of the distance between the through holes and the distance between the communication hole and the air intake hole.