To provide a radio controlled timepiece and its control method allowing to perform time correction and time difference correction without requiring a user of the radio controlled timepiece to pay attention to morning/afternoon to provide excellent operability by automatically determining the morning/afternoon of a time before an operation of receiving a standard time and frequency signal and allowing high reliability by setting the beginning of the reception of a standard time and frequency signal at midnight ensuring a good receiving environment.

The radio controlled timepiece comprises a receiving section 20 which receives a standard time and frequency signal including standard time information, clocking means 32 which times clocking information P10 having a 24-hour period including morning/afternoon information on the basis of standard time information P6 obtained by the receiving section 20, input means 5 which corrects the clocking information P10 of the clocking means 32, a display section 3 which displays a time with a 12-hour period on the basis of the clocking information P10 from the clocking means 32, a solar cell 23 which detects external light, and morning/afternoon determination means 33 which determines the morning/afternoon information of the clocking means 32 according to an output from the solar cell 23.