Carbon membranes, among various types of inorganic membranes, exhibit an excellent gas separation performance, and can be used in an environment where organic membranes cannot be used and heat resistance and chemical resistance are required. Therefore, the practical application thereof is expected. Further, hollow fiber membranes have an excellent pressure resistance and a large membrane area per unit volume, and thus have characteristics that they can be used to produce separation membrane modules which are more compact than those produced with flat membranes or spiral membranes.
Hollow fiber carbon membranes have been reported to have problems such as membrane fragility, sealing difficulty, and cost. In order to solve these problems, there have been proposed: a hollow fiber carbon membrane in which an inexpensive polyphenylene oxide derivative is used for forming a precursor (see Patent Document 1); a flexible hollow fiber carbon membrane in which a sulfonated polyphenylene oxide derivative is used for forming a precursor (see Patent Document 2), and the like.