We investigated terahertz pulses from a rotating fan-out type poled lithium niobate (LiNbO(3)) pumped by femtosecond laser pulses. In particular, the rotating fan-out type poled sample produces an uncertain phase-matching wave vector perpendicular to input laser pulses. Such a wave vector allowed us to observe terahertz pulses normally unobservable from bulk or periodically poled LiNbO(3) at large rotation angles because of the terahertz wave critical angle of LiNbO(3). Further, we explained center frequency dependence on rotation angles by difference frequency generation process with the uncertain wave vector. We also discussed bandwidth dependence and terahertz pulse power regarding rotation angles.