A terminal device (1; 1a) comprising: a position detection unit that detects a current position of the terminal device; an environmental-information acquisition unit that acquires environmental information of the terminal device, the environmental information including a moving speed of the terminal device, and ambient temperature and humidity of the terminal device; a storage unit (15; 15a) that stores therein information of behavior patterns of a user of the terminal device, information of control patterns of an air conditioner associated with the behavior pattern so as to set at least one of a temperature, a humidity, and an air volume of the air conditioner, and air-conditioner position information; a control unit (16; 16a) that estimates an arrival time at which the user arrives at a position of the air conditioner based on the current position, a moving speed included in the environmental information, and the air-conditioner position information, estimates a behavior pattern of the user by using the moving speed, and decides a control pattern of the air conditioner based on the acquired ambient temperature and/or humidity and the estimated behavior pattern, to generate a control signal including control information to the air conditioner based on the arrival time and the estimated control pattern; and a wireless communication unit (17; 17a) that transmits the control signal generated by the control unit (16; 16a) to the air conditioner, wherein the control unit (16; 16a) changes control content to the air conditioner according to whether the current position is within a specific area, which is set as an extent where the air conditioner is remotely controlled, wherein, when the control unit has determined that the current position of the terminal device is within the specific area, the environmental-information acquisition unit acquires the environmental information of the terminal device, and, when the control unit has determined that the current position of the terminal device is outside the specific area, the control unit generates a control signal to stop the air conditioner. a position detection unit that detects a current position of the terminal device; an environmental-information acquisition unit that acquires environmental information of the terminal device, the environmental information including a moving speed of the terminal device, and ambient temperature and humidity of the terminal device; a storage unit (15; 15a) that stores therein information of behavior patterns of a user of the terminal device, information of control patterns of an air conditioner associated with the behavior pattern so as to set at least one of a temperature, a humidity, and an air volume of the air conditioner, and air-conditioner position information; a control unit (16; 16a) that estimates an arrival time at which the user arrives at a position of the air conditioner based on the current position, a moving speed included in the environmental information, and the air-conditioner position information, estimates a behavior pattern of the user by using the moving speed, and decides a control pattern of the air conditioner based on the acquired ambient temperature and/or humidity and the estimated behavior pattern, to generate a control signal including control information to the air conditioner based on the arrival time and the estimated control pattern; and a wireless communication unit (17; 17a) that transmits the control signal generated by the control unit (16; 16a) to the air conditioner, wherein the control unit (16; 16a) changes control content to the air conditioner according to whether the current position is within a specific area, which is set as an extent where the air conditioner is remotely controlled, wherein, when the control unit has determined that the current position of the terminal device is within the specific area, the environmental-information acquisition unit acquires the environmental information of the terminal device, and, when the control unit has determined that the current position of the terminal device is outside the specific area, the control unit generates a control signal to stop the air conditioner.