To provide a method of manufacturing a novel laminate.

This invention relates to a method of forming film or sheet of thermoplastic polymer alloy, in which a tight blend of a polymer material P1' and a polymer material P2' is formed and the blend is extruded through a die and the flow is caused to flow through a die including an outlet orifice having an outlet gap, wherein a grid chamber having at least one grid, through which the blend passes, is provided on the upstream of the outlet orifice, one or a plurality of grids have openings of sizes selected so as to reduce an average size of dispersed phases of P1' or P2' in the blend, the one or the plurality of grids exist on positions having gaps wider than an outlet gap in the chamber, the grid chamber further has a part where the gap decreases between a screen and a die outlet, and the gap through which the blend passes is reduced at least on a part of a path to the gap of the die outlet.