A method of separating perfluorotripropylamine from a mixture B, the mixture B containing perfluorotripropylamine and a mixture A containing at least one selected from the group consisting of a hexafluoropropene trimer represented by C9F18, a perfluoroalkene ether, and a perfluoropolyether, where a coagulation point of the mixture A is a temperature equal to or less than a coagulation point of the perfluorotripropylamine, and separating the perfluorotripropylamine from the mixture A is carried out at a temperature equal to or less than the coagulation point of the perfluorotripropylamine.