A pet restraining harness sytem for restraining a pet traveling in a vehicle having a seat belt with a buckle. The magnitudes, polarities, and positions of the magnetic or electric field sources are configured to have desirable correlation properties, which may be in accordance with a code. When an initial engine rotation speed is smaller than the target engine rotation speed, the controller causes the target relative rotation speed to gradually vary from an initial relative rotation speed to a predetermined target change-over relative rotation speed. To secure a ribbon about a package with the tie member, a free end of the ribbon is threaded through an inner opening from the underside surface of the tie member to and through the exposed decorative surface of the tie member. The first differential amplifier circuit outputs a signal to turn on the second MOS transistor when the first divided voltage is higher than the reference voltage, and the first differential amplifier circuit outputs a signal to turn off the second MOS transistor when the first divided voltage is lower than the reference voltage.