To disposal waste plastics recovered on an accumulation site into a shape suitable for conveyance and storage.

A plastics crushing plant consists of a supply conveyor 1, a crusher 2, a conveyor 3 for crushed plastics, a washer-dehydrator 4 for washing crushed plastic pieces with water to separate washing water, an air feeder 5 and a cyclone 6. The plant is constituted of the bed 8 of a cargo transport vehicle or trailer vehicle. As the washer-dehydrator 4, it is desirable to utilize a vertical centrifugal washer-dehydrator. An adhered substance does not diffuse a malodor on the way of feed of during keeping and there is not danger such as natural ignition or the like. Since a waste plastics disposal vehicle and a transport vehicle are separated, this plant is economical and develops economical efficiency enhancing effect of recycling.