Disclosures of the present invention describe a switch device has a controlling and processing unit comprising a first zero point detector, a second zero point detector, an arc detector, and a microcontroller. According to zero crossing point of input voltage signal, zero crossing point of output voltage signal, relay's delay time, and arc-spark-induced signal, the microcontroller is capable of adaptively generating a relay controlling signal to control the relay, such that the relay achieves a short-circuit switching at the zero cross point of output voltage signal for making the output voltage signal be transmitted to at least one load device. Moreover, the microcontroller is also able to control the relay to finish a short-circuit switching at the zero cross point of input voltage signal, so as to stop the output voltage signal from being transmitted to the load device.