This paper proposes an algorithm to automatically detect synchronization error that can be occurred in the stereoscopic video system. Specially, this paper is aiming toward 3DTV broadcasting system that requires a real-time operation with high accuracy. Accordingly, we propose new similarity calculation algorithm by applying the spatiogram concept, which is proper to the sync error detection at stereoscopic video with real-time operation. In this paper, the spatiogram includes temporal information to increase an accuracy of sync error detection. This paper also introduces an implementation of stereoscopic video synchronizer for the purpose of practical use, which performs the sync error correction function. Finally, the proposed algorithms are evaluated and verified through an implemented of 3DTV experimental system.