An extruder which can be applied to various types of resin and elastomer without having to replace a die is provided. An extruder of the present inventions has: a barrel to which raw material, that is raw elastomer or raw material resin, is supplied; a screw that is driven to rotate in the barrel in order to process the raw material together with the barrel; and die 5 that is provided at a discharge point of the barrel and that discharges the raw material that has been processed. Die 5 includes first flat plate 11 having at least one first hole 13 and second flat plate 12 having at least one second hole 14, wherein first flat plate 11 and second flat plate 12 are arranged adjacent to each other along longitudinal axis X1 of the barrel, and at least either first flat plate 11 or second flat plate 12 is movable relative to the other flat plate such that an overlapping part of first hole 13 and second hole 14 can be varied.