To provide a method for preventing acquisition of synchronization with an interference wave, which enhances the holding capability of a synchronous position based on window ranges and thresholds not to acquire synchronization with the interference wave.

In the method for preventing synchronization pull-in to an interference wave, correlation values between a preliminarily prepared synchronizing word and a received synchronizing word are calculated, a maximum correlation value of calculated correlation values is defined as a first maximum correlation value, a prescribed window range is provided before and after the first maximum correlation value, and the first maximum correlation value is compared with a first prescribed threshold. The first maximum correlation value is defined as a synchronous position when the former is the larger. When the former is equal to or larger than the first prescribed threshold, maximum one of calculated correlation values on the outside of window ranges is defined as a second maximum correlation value, and the second maximum correlation value is compared with a second prescribed threshold. When the former is the larger, the first maximum correlation value is defined as a synchronous position. When the second maximum correlation value is equal to or larger than the second prescribed threshold, the end of reception of the received synchronizing word is decided to perform synchronization terminating processing.