Zigzag microchannels are commonly used in microreactor and mu TAS, because they are the simplest structures that can function both as a path for liquid transportation and a fluid mixing device. In ordinary zigzag channels, the bending direction alternates, and as a result, the convective fluid mixing effect at one bend is partially cancelled at the next bend. Therefore, the zigzag channel with m alternating bends does not exhibit m times as much mixing performance as a channel with a single bend even. In this study, the mixing performance of four special types of zigzag channels was compared. These channels had m successive 90 degrees bends in the same direction, then m successive 90 degrees bends in the opposite direction, and this pattern was repeated numerous times. Experiments with channels having m(-1), 2, 3, or 4 were performed to determine mixing efficiency and the flow condition as Re number.