a method for preparing a fluoropolymer aqueous dispersion , including : step of preparing a fluoropolymer aqueous dispersion comprising a fluoropolymer having at least one selected from the group consisting of — so 2 y and — coor by emulsion polymerization ; step of heating the fluoropolymer aqueous dispersion to 50 ° c . or higher ; and step of contacting the fluoropolymer aqueous dispersion with an ion exchange resin for cation exchange after step , thereby providing a purified fluoropolymer aqueous dispersion , the fluoropolymer aqueous dispersion being adjusted to ph 7 or lower from the end of the polymerization in step to the end of step .