PROBLEM TO BE SOLVED: To obtain a new fluorine-containing monomer from which a highly functional fluorine-containing polymer can be synthesized.
SOLUTION: This fluorine-containing monomer is represented by formula I (RF is an alkyl or aralkyl, having at least two fluorine atoms). A perfluoroalkyl, e.g. (CF2)6F is cited as the alkyl capable of being introduced into formula I as RF, and CF2Ph is preferably cited as the aralkyl. For example, 2,5-bis (α, α-difluorophenylmethyl)bicyclo[5. 2. 0]nona-1.5.7-triene is cited as the monomer of formula I. The monomer of formula I is obtained, for example, by fluoroalkylating a compound of formula II (L1 is an eliminable group; P is a protective group) to provide a compound of formula III (R1 is a fluoroalkyl having at least two fluorine atoms), converting the carbonyl carbon of the compound of formula III to an ethylenic carbon, deprotecting and dimerizing the resultant product.