Synchronization of a spiral by a circularly polarized electric field (CPEF) in reaction-diffusion systems is investigated since they both possess rotation symmetry. It is found that spirals in different regimes (including rigidly rotating, meandering, and drifting spirals) can be forced to be rigidly rotating ones by CPEFs. Moreover, the rotational frequency of the entrained spiral is found to be synchronized with the frequency of the electric field in a ratio of 1:1.