Abstract: An aspect of the invention provides a wet medium stirring, crushing, and dispersing machine achieving a high crushing and dispersing effect and high processing efficiency even in a low stirring member stirrer tip speed at which a processed material is not damaged, without particularly increasing the cost. In the wet medium stirring, crushing, and dispersing machine in which beads and slurry are caused to flow to crush and disperse the processed material in the slurry by rotation of a stirring member mounted in a crushing vessel, a small through-hole is made in order to rapidly narrow a flow passage of an in-flow fluent material to generate an orifice contracted flow, and the orifice contracted flow disturbs vectors of the flowing beads to effectively increase a speed difference ?V between the beads, thereby securing and improving the desired crushing and dispersing effect and the processing efficiency even in the low stirrer tip speed operation.