NOVELTY - Producing a photoelectric conversion element (10) comprises: applying a semiconductor fine particle dispersion liquid, in which the content of solids excluding semiconductor fine particles is 10% by mass or less based on the total amount of the semiconductor fine particle dispersion liquid, on the electrically conductive support, to form a coating; heating the coating, to obtain porous semiconductor fine particles; and sensitizing the porous semiconductor fine particles by adsorption of a dye, which is a heterocyclic compound (A).    USE - The method is useful for producing a photoelectric conversion element, which is useful in a photoelectrochemical cell (claimed).    ADVANTAGE - The photoelectric conversion element has high conversion efficiency.    DETAILED DESCRIPTION - Producing a photoelectric conversion element (10) comprising a laminated structure including an electrically conductive support (1), a photosensitive layer (2) having porous semiconductor fine particles that have adsorbed a dye, and formed on the electrically conductive support, a charge transfer layer (3) and a counter electrode (4), comprises: applying a semiconductor fine particle dispersion liquid, in which the content of solids excluding semiconductor fine particles is 10% by mass or less based on the total amount of the semiconductor fine particle dispersion liquid, on the electrically conductive support, to form a coating; heating the coating, to obtain porous semiconductor fine particles; and sensitizing the porous semiconductor fine particles by adsorption of a dye, which is a heterocyclic compound of formula (A).    X = non-metallic atoms necessary for forming a nitrogen-containing 7-membered ring by linking with the benzene rings, preferably -CH2-CH2-;    Y1 = dye residue;    n = 1 or more;    Z = substituent;    m = 0 or positive integer; and    R1 = H, aliphatic group, aryl or heterocyclyl that is linked with the nitrogen atom via a carbon atom.    DESCRIPTION OF DRAWING(S) - The figure shows a cross-sectional view of the photoelectric conversion element produced by the method.    Electrically conductive support (1)    Photosensitive layer (2)    Charge transfer layer (3)    Counter electrode (4)    Photoelectric conversion element. (10)