NOVELTY - Photoelectric conversion element comprises an oxide semiconductor fine material sensitized with a methine dye.    USE - Used in the production of solar cells.    ADVANTAGE - The element shows a conversion efficiency comparable or better than known elements sensitized with a methine dye. A solar cell with high conversion efficiency and high stability is obtained.    DETAILED DESCRIPTION - The methine dye is of formula (I)-(IV);    Rg1 = a group (V)-(VII);    Rg2 = a group of formula (VIII);    Rg3 and Rg4 = group of formula (IX);    asterisk = the position which bonds with the methine group;    A1-A10 = optionally substituted aliphatic hydrocarbon group, optionally substituted aromatic hydrocarbon group, optionally substituted heterocyclic group, optionally substituted amino group, OH group, alkoxy group, H, halogen, cyano group, alkoxycarbonyl group or acyl group, or may form an optionally substituted ring;    X1-X6 = O, S, Se or -NR''-;    X7 = O, S, Se, -CRR', -CR=CR'- or -NR'';    R' and R'' = H or a substituent;    Y1 and Y2 = optionally substituted aromatic hydrocarbon group or organometallic complex residual group;    Y4 = optionally substituted aromatic hydrocarbon group, optionally substituted heterocyclic residual group or optionally substituted organometallic complex residual group;    R1, R4 and R5 = H, cyano group, optionally substituted aliphatic hydrocarbon group, optionally substituted aromatic hydrocarbon group, optionally substituted heterocyclic group, carboxyl group, carbonamide group, alkoxycarbonyl group or acyl group;    R2, R3, R6 and R7 = H, optionally substituted aliphatic hydrocarbon group, optionally substituted aromatic hydrocarbon group, or optionally substituted heterocyclic group;    R8 = carboxyl group, alkoxycarbonyl group or aryloxycarbonyl group;    R9 = H or a substituent;    R10 = carboxyl group or hydroxyl group;    n1 and n4 = 0-4;    n2 and n3 = 1-4;    n5 = 0, 0.5 or 1;    n6 = an integer 1-3;    Z = a counterion.    INDEPENDENT CLAIMS are also included for:    (1) a solar cell using this element; and    (2) the oxide semiconductor fine material sensitized with a methine dye.