An electronic device includes a solar cell, a secondary battery that is charged by the solar cell, and a control circuit that switches between a charging period during which the charging of the secondary battery from the solar cell is performed and a communication period during which an optical signal is received by the solar cell. The optical signal includes a synchronization signal indicating the transmission of data and the data, and the communication period is configured to detect the synchronization signal. The control circuit extends the communication period to enable the solar cell to receive the whole data included in the optical signal.