PURPOSE: To mold easily a molded product, large and of complicated shape by laminating successively layers composed of (A) a polyolefin layer, (B) a layer composed of a mixture of resin not compatible with polyolefin and polyolefin resin substituted with alkylcarboxyl and (C) a polyolefin resin layer.

CONSTITUTION: As for polyolefin resin constituting a layer (A), for example, a single polymer of α=olefin such as, for example, ethylene or propylene or a copolymer of them is used. As for a layer (B), a mixture of resin not compatible with polyolefin resin and polyolefin resin substituted with alkylcarboxyl is used. As for resin not compatible with polyolefin resin, for example, polyamide resin is used. As for the polyolefin resin constituting a layer (C), the polyolefin constituting the layer (A) can be used, which can be same as the polyolefin resin for the layer (A) or different. Said laminate is formed by laminating successively the layer (A), the layer (B) and the layer (C).