PURPOSE: To easily obtain a gluten sheet having biodegradability by a method wherein wheat gluten and a plasticizer are mixed to be cured under heating and pressure and the obtained molded block is rotated and a cutting blade is pressed to the side peripheral surface parallel to a rotary shaft of the block.

CONSTITUTION: A wheat gluten powder and a plasticizer are masticated to be cured under heating and pressure to form a cylindrical body 1. A rotary shaft 3 is inserted in the hollow hole 2 of the cylindrical body 1 to support the cylindrical body 1 on the rotary shaft 3 by a key groove 4 so as to be rotatable along with the rotary shaft 3. A wide cutting blade 5 having a pointed edge 7 is attached to an edge tool holder and the cylindrical body 1 is rotated around the rotary shaft 3. The cutting blade 5 is pressed to the side peripheral surface of the cylindrical body 1 and a thin skin is peeled from the surface of the molded object 1 in which the cutting blade 5 is thrust to continuously form a gluten molded sheet 10 having the width corresponding to the length of the pointed edge 7. By this constitution, a flexible sheet can be simply and rapidly produced.