It is an object of the present invention to provide a resin molded body capable of appropriately and easily improving strength compared to the prior art. The resin molded body according to the present invention includes first phases (21, 24) in which convex and concave parts extend in substantially linear directions (D, E), observed within a measurement range (A) of 5 μm×5 μm arbitrarily selected on a resin cross section and the first phases account for 50% or more. The first phases are preferably in a crystalline state. A second phase made of an amorphous substance (25) is preferably interposed between the first phases.