This paper deals with the experiment of the flow induced force of interlocking type labyrinth seals. The test apparatus was made so that the shaft could rotate and whirl at the same time in the seal for obtaining the dynamic properties. The test was performed on a multi-stage labyrinth seal such as is used in a balance piston or a center seal in a centrifugal compressor. After ascertaining the data accuracy, the leakage flow was measured, and the dynamic properties were also measured by changing whirl speed, whirl amplitude, rotating speed, entrance swirl velocity and pressure difference. The measured force was separated into the tangential force (stability force) and radial force (restoring force), and their characteristics are discussed and compared with straight-type seals.