Flow visualization studies in intersecting ducts have been conducted to disclose the mechanics of the flow phenomena in the intersecting zone. In this study, experiments in two intersecting ducts with a cavity inclusive of a splitter are performed to investigate the secondary flow in the cavity and the flow rates in the left and right downstream ducts when changing the conditions of the shapes of cavity, the intersecting angles and the upper water levels. The flow pattern in the cavity is visualized by the particle tracing method. The velocity distribution in the cavity is measured by the two-dimensional Laser Doppler velocimetry. The flow rates in the downstream ducts are measured by hydrometry. The secondary flow and the flow characteristics in the cavity are clarified.