Method of manufacturing extrusion molded product

A method of manufacturing an extrusion molded product, the method comprising:

• a step of pulling a core member by a first puller, the core member being made of a resin and molded into a desired shape in a first die;
• and
• a step of molding an extrusion molded product by providing a covering portion made of a thermoplastic elastomer over an outer periphery of the core member, which has been pulled by the first puller, in a second die and pulling the extrusion molded product by a second puller,
• wherein a sensor unit that monitors tension in the core member is provided between the first puller and the second puller, and at least one of the first puller and the second puller adjusts, based on the tension in the core member monitored by the sensor unit, a pulling speed such that the tension in the core member between the first puller and the second puller falls within a normal range.