To prevent damage of a seal by particles in a medium sent and supplied by a pump by arranging a spiral notch on a mantle surface of a cavity in a seal housing for a mechanical seal device, and sending and supplying the particles in liquid in the direction for separating from the seal device.

In a device arranged in a seal housing for a rotating machine such as a pump, and in the device which has the seal housing arranged in a cavity in a housing and whose cavity is opened toward a pump impeller, a notch or a shoulder 11 extending along a surface by forming a spiral pattern is arranged on a mantle surface 12 of the cavity. Therefore, in the case where particles entering the cavity are carried toward a bottom part of the cavity by a boundary layer flow, when the particles collide with the shoulder 11, these particles are moved inward in the radial direction. These are captured by the pump impeller, and are discharged by passing through an expanding slot between the pump impeller and the seal housing by centrifugal force.