It is made possible to designate erasure or updating of the communication parameters. According to the control method, the portable telephone periodically measures a power level of a radio frequency received from an earphone when a loss prevention mode is determined, and detects a calling state between the portable telephone and the earphone. A cover is attached to the base. Gaps are formed between adjacent upright supporting portions, and ribs are provided between the adjacent upright supporting portions, thus allowing cut hair to be discharged out of the inner cutter through openings defined by the adjacent upright supporting portions and ribs. Low electric energy consumption and pollutant emission, easy operation and low production costs are achieved. Application to a family wallet system allowing children to participate to electronic commerce.