an object of the invention is to provide a method and an apparatus for recycling plastics which is improved with respect to operation efficiency , operation environment , lowering degradation of plastics , recycling cost and environment load including saving energy . the recycling is made as follows : coarse - crushing used - up plastic products , separating plastic materials from other foreign matters by air blow separation , fine - crushing the separated plastics , washing the fine - crushed plastics by the process using a circulation flow including a spiral flow in which interaction between crushed plastics helps themselves clean without washing agents , dewatering the washed plastics , drying them , removing metallic matters by using metal detector , then feeding them directly without pelletizing to an injection molding machine of which nozzle part is equipped with filter and flow - switching mechanism for cleaning the filter by backwash reverse filtration .