PURPOSE: To manufacture the rolled product with uniform thickness, without leaving roundness in the breadth end part, by extruding the raw material so as to form the breadth end parts to be thicker than the middle part, and then, by rolling this raw material.

CONSTITUTION: The extrusion die 1 has the die opening 4 which forms at the breadth end parts the increased thickness part 3 thicker than the middle part of the raw material 2 extruded by this die 1. The raw material 2, which is extruded by this die 1 so as to have the increased thickness pats 3, is rolled by the rolling roll 5, 6; hereupon, the breadth end parts are previously provided with the increased thickness part 3, so that the reduction of thickness due to the roundness caused in the breadth end parts can be prevented; hereby, the rolled product 7 with uniform thickness can be manufactured.