PROBLEM TO BE SOLVED: To provide a radiowave correction timepiece and a code determination method therefor, which are capable of reducing erroneous determination of a code.SOLUTION: A radiowave correction timepiece 1 includes: reception means 5 for outputting a reception signal by receiving a standard radiowave containing clock-time information; start timing setup means 13 for setting sampling-start timing on the basis of second-synchronization timing; maximum-width signal detection means 14A for detecting a maximum-width signal of which a signal width of a first level is the maximum, from among reception signals received within a given period from the sampling-start timing; determination timing setup means 14B for setting determination timing within a period in which the maximum-width signal is transmitted; elapse time detection means 14C for detecting elapsed time from the sampling-start timing to the determination timing: and code determination means 15 for determining a code of a signal in a period of one
