To provide a method for preparing a multi-layer inflation film with excellent productivity and good quality by using a 4-methyl-1-pentene polymer.

In a method for preparing a multi-layer inflation film, a 4- methyl-1-pentene polymer (A), an adhesive resin (B) and an ethylene polymer (C) with a melt tension of at least 30 mN measured at 190°C are co-extruded to mold an inflation and a multi-layer film consisting of a layer consisting of (A), an intermediate layer consisting of (B) and a layer consisting of (C) is obtained.