NOVELTY - A fluorine-containing adamantane derivative (I) is new.    USE - New fluorine-containing adamantane derivative is used for resin composition for forming cured material used for anti-reflective film (all claimed). Uses include but are not limited to optical fiber, optical waveguide, lens, volume hologram, hologram memory material, surface modifying agent, industrial tube material, sealing material, liquid crystal display and electrolytic membrane of solid polymer fuel cell.    ADVANTAGE - The cured material of resin composition containing fluorine-containing adamantane derivative, has low refractive index and excellent heat resistance and surface hardness.    DETAILED DESCRIPTION - A fluorine-containing adamantane derivative of formula (I) is new.    R1,R2=H, aliphatic hydrocarbyl (optionally substituted with halo, O or hydroxy) or -(G2-(C(-R3)(-R4))e)f-X1;    X1=-O-C(=O)-C(-R5)=CH2 or organic group of formula (i) or (ii);    a=1-4;    b=10-15;    a+b=16;    c,d=1-10;    G1,G2=single bond, hetero atom, or bivalent group containing hetero atom;    R3,R4=R1;    e,f=0 or 1-10;    R5=H, methyl or trifluoromethyl;and    R6=1-5C hydrocarbyl.    When a is 1-4, at least 2 or more of R1 and R2 are organic groups of formula: -(G2-(C(-R3)(-R4))e)f-X1 and 3 or more of X1 are group of formula (i) or (ii). INDEPENDENT CLAIMS are included for the following:    (1) manufacture of fluorine-containing adamantane derivative (I);    (2) fluorine-containing adamantane derivative of formula (II);    (3) manufacture of fluorine-containing adamantane derivative (II), which involves reacting fluorine-containing compound chosen from perfluoro adamantane monool, perfluoro adamantanediol, perfluoro adamantanetriol and perfluoro adamantane tetraol, with halogen-containing alcohol compound;    (4) resin composition, which contains fluorine-containing adamantane derivative (I); and    (5) cured material, which is obtained by hardening the resin composition .    R7,R8=H, aliphatic hydrocarbyl (optionally substituted with halo, O or hydroxy) or -(G2-(C(-R3)(-R4))e)f-OH.    When a is 1-4, at least 2 or more of R7 and R8 are organic group of formula: -(G2-(C(-R3)(-R4))e)f-OH.