Method for producing fluorine-containing copolymer

A method of producing a fluorine-containing copolymer, the method comprising performing suspension polymerization using monomers comprising ethylene and tetrafluoroethylene in a polymerization medium comprising water and a polymerization solvent A that is not compatible with water and that is at least one kind selected from the group consisting of compounds represented by the following Formulae 1 to 3,

• wherein a proportion of water to the polymerization medium is from 10% by volume to 80% by volume:
• wherein, in Formula 1, Y1 represents a nitrogen atom or an oxygen atom,
• in a case in which Y1 is a nitrogen atom, each of p, m, n, and k is independently an integer satisfying p+m≥1 and p+m+n+k=3,
• in a case in which Y1 is an oxygen atom, k is 0, and each of p, m, n, and k is independently an integer satisfying p+m≥1 and p+m+n=2,
• in a case in which p is 1 or more, n is 1 or more,
• in Formula 2, Y2 represents a carbon atom, a silicon atom, a phosphorus atom, or a sulfur atom,
• in a case in which Y2 is a carbon atom or a silicon atom, each of s, t, u, and vis independently an integer satisfying s+t≥1 and s+t+u+v=4,
• in a case in which Y2 is a phosphorus atom, each of s, t, u, and v is independently an integer satisfying s+t≥1 and s+t+u+v=3,
• in a case in which Y2 is a sulfur atom, each of s, t, u, and v is independently an integer satisfying s+t≥1 and s+t+u+v=2,
• in a case in which s is 1 or more, u is 1 or more,
• each X independently represents a chlorine atom or a bromine atom,
• in Formulae 1 and 2, each Z′ is independently a group represented by any one of the following Formulae T1 to T6,
• in Formula 3, Y3 represents a carbon atom or a silicon atom, and
• each of R1 to R4 independently represents a methyl group, a tert-butyl group, or a tert-butoxy group:
• wherein, in Formulae T1 to T6, each A1 independently represents a hydrogen atom, a methyl group, a tert-butyl group, —OR, or —NR2, each A2 independently represents a methyl group, a tert-butyl group, —OR, or —NR2, each R independently represents a methyl group or a tert-butyl group, and * represents a binding site.