To manufacture a composite resin sheet having no external appearance fault with high productivity by setting same a projecting length in a specific direction of a resin strip over a specific direction, and changing a distance from a central position of the strip in the specific direction to one surface of a sheet over a specific direction.

A discharge amount of a resin for a resin layer A receives channel resistances of a channel and a slit. Thus, the amount proportional to a height of the slit is discharged. Accordingly, a distance (s) between a central position of a resin strip in a Y direction and one surface of a sheet can be changed in a width direction of a sheet. Here, as a resin for the strip, a resin having a different refractive index from that of the resin for the layer A is used. A light incident toward an X direction of the sheet from a sheet edge is reflected or refracted at an interface between the strip and the layer A, and lights aligned in a predetermined direction of the sheet are emitted with a uniform intensity of the X direction. Thus, the composite resin sheet having a uniform thickness and no external appearance fault can be simply manufactured with a high productivity.