To enable indoor and outdoor physical conditions to be detected for very fine control thereof. Self-contained transmitting sensors 10-1 through 10-8 which monitor physical quantities and convert them into electrical data signals for radio-transmission are disposed in desired positions in housing. The wirelessly transmitted data signals are received by a portable information terminal 20 for controlling the operation of a device 30 to be controlled based upon the received information and its information history. By wearing a self-contained transmitting sensor 10-9 on a user 40 physical quantities such as temperature, humidity and illumination at a place in which the user is located can be controlled to desired values wherever the user moves.