To make transparency excellent by improving mechanical properties by raising further a draw ratio by a method wherein after drawing a sheet having polyolefin as a main constituent, the sheet is compressed heating at a temperature within a specific range one.

After melting polyolefin wherein polypropylene or the like is mixed in high density polyethylene, a raw fabric sheet to be molded is inserted between mill rolls and drawn by rolling in a length direction reducing a thickness. The rolled sheet is drawn being heated with hot blast or infrared radiation or the like. Further, the drawn sheet is inserted between heating rolls wherein a clearance between the rolls is narrower than the thickness of the sheet, and the rolls are rotated in mutual reverse directions. Where a melting point of the polyolefin is T°C, it is compressed heating at a temperature within a range of (T-25)°C to (T+5)°C. A polyolefin sheet which is excellent in transparency and excellent in mechanical properties such as tensile strength, tensile elasticity, etc., is obtained.