Method of manufacturing resin pipe

A method of manufacturing a resin pipe using a die slide injection mold configured such that positions at which molds to be assembled together during primary molding and secondary molding are slid, in which the resin pipe is manufactured by:

• forming two molded articles in a cylindrical two-piece split shape by injecting a primary resin that is molten into two primary cavities that are formed by the molds assembled together during the primary molding;
• internally fitting the two molded articles in a cylindrical shape into one secondary cavity formed by the molds assembled together during the secondary molding such that the molded articles are located opposed to each other via a space between the molded articles, injecting a secondary resin that is molten into the secondary cavity, and then injecting an assist material into the secondary cavity;
• the assist material passes, and thus the inner circumferential surface of the secondary resin that has not yet completely cured is molded into the desired shape;
• integrating an inner surface layer formed of the secondary resin, that has cured, with the two molded articles,
• wherein the molded articles having a desired outer shape are molded during the primary molding, and by integrating the inner surface layer formed of the secondary resin cured during the secondary molding with the two molded articles, a portion having any desired shape can be manufactured on an outer circumferential surface of the resin pipe in a two layer structure formed of the inner surface layer and the outer surface layer.