Fluorinated polymer

A water- and oil-repellent agent comprising a fluorine-containing polymer comprising a repeating unit derived from a fluorine-containing monomer (f) represented by the formula:

• wherein, independently at each occurrence,
• Xf is a hydrogen atom, a monovalent organic group or a halogen atom,
• Yf is a 1+α valent group composed of one or more selected from the group consisting of Yf1 and Yf2, but comprises at least one Yf2,
• Yf1 is a group composed of one or more selected from the group consisting of a direct bond, —O—, —C(═O)—, —C(═NR′)—, —S—, —S(═O)2—, —NR′—, —C(OR′)R′—, —C(OR′) (−)2 and —N(−)2, wherein R′ is a hydrogen atom or a monovalent organic group,
• Yf2 is a group composed of one or more selected from a divalent to tetravalent aliphatic hydrocarbon group having 1 to 20 carbon atoms, a divalent to tetravalent hydrocarbon aromatic ring optionally having a substituent, and a divalent to tetravalent heterocyclic ring optionally having a substituent,
• Zf is Rf1, or a hydrocarbon group having 2 or more and 40 or less carbon atoms and including Rf1 or Rf2, and
• α is 1 to 3,
• wherein
• Rf1 is —CF3, —CF2H or —CFH2,
• Rf2 is —CF2— or —CFH—, and
• Rf1 and R12 do not constitute a moiety of a fluoroalkyl group having 2 or more carbon atoms or —CH2—CF2—CH2—.