An electronic appliance includes a microphone which detects a clapping sound, an edge signal extractor, an edge pulse generator and a judgment processing circuit. The judgment processing circuit generates a first gate having a first time width to detect whether or not a second clapping sound has been generated after elapse of a first predetermined time from a first time when the microphone detects a first clapping sound and the edge pulse generator generates the first edge pulse corresponding to the first clapping sound. Subsequently, the judgment processing circuit generates a second gate having a second time width to detect whether or not a third clapping sound has been generated after elapse of a second predetermined time from a second time when the edge pulse generator generates the second edge pulse corresponding to the second clapping sound.