An automatic window opening/closing system includes a motor for driving a window. In association with the window, a pressure responsive sensor (preferably, a pressure responsive sensor with a coaxial structure having uniform sensitivity to pressures in all directions) is provided. A detector circuit is coupled to the pressure responsive sensor and evaluates a rate of change of a pressure on the sensor, thereby detecting a squeezed object caught in a way of the window during an operation of the system. A motor control circuit is provided to control the motor in response to a squeezed object detection signal from the detector circuit in such a direction to release the object from the window. The motor control circuit detects an overload condition of the motor in accordance with a motor terminal voltage and deenergizes the motor to prevent the motor from generating heat. Therefore, this system achieves improved performance, high reliability and safety.