To process the sucked and recovered sludge reliably and efficiently by separating the solid part of the sludge sucked and recovered from the water bottom together with water from water at a high ratio quickly and reliably.

A separation chamber 4 opened on the upper face and a box frame 3 formed with an outflow port 6 are provided on the deck 2 of a hull 1. The separation chamber 4 is provided with a separation body 12 formed with a screen material 13 solid-liquid-separating the sludge by a filtering action and developed to an inclined sheet shape when drawn from the box-like storage state. The box frame 3 is provided with a discharge chute 19 for the separated solid part on one side and lifting functional bodies of the separation body 12 on the other side respectively to achieve the reliable solid-liquid separation by utilizing the gravitational force of the sludge and the quick discharge of the separated solid part.