A dye-sensitized solar cell for low illumination, comprising: a first electrode comprising a transparent substrate and a transparent conductive film provided on the transparent substrate; a second electrode that faces the first electrode; an oxide semiconductor layer that is provided on the first electrode or the second electrode; an electrolyte that is provided between the first electrode and the second electrode; a photosensitizing dye that is adsorbed to the oxide semiconductor layer; and a co-adsorbent that is adsorbed to the oxide semiconductor layer together with the photosensitizing dye, the photosensitizing dye being a metal complex compound represented by the following formula, characterized in that the co-adsorbent comprising two kinds of organic compounds selected from the group consisting of an organic compound represented by the following formula, an organic compound represented by the following formula, and an organic compound represented by the following formula or comprising an organic compound selected from the organic compounds represented by formulas to and an organic compound represented by the following formula:: wherein in formula, M represents Ru; R 1, R 2, R 3, and R 4 each independently represent a monovalent cation; and R 5 and R 6 each independently represent a halogen group, -H, - CN, -NCS, or -NCO; wherein in formula, n represents an integer from 0 to 5; and R 7 represents a monovalent group having a π-conjugated structure, or a monovalent group having a steroid skeleton; wherein in formula, W represents a carbon atom or a silicon atom; Y 1, Y 2, Y 3, and Y 4 each independently represent a hydrogen atom, a carboxyl group, a substituted or unsubstituted alkoxy group having 1 to 6 carbon atoms, or a substituted or unsubstituted hydrocarbon group having 3 to 20 carbon atoms; and one of Y 1, Y 2, Y 3, and Y 4 represents a substituted or unsubstituted hydrocarbon group having 3 to 20 carbon atoms, while at least two of the remaining groups each represent a carboxyl group or a substituted or unsubstituted alkoxy group having 1 to 6 carbon atoms; wherein in formula, Y 5, Y 6, and Y 7 each independently represent a hydroxyl group or a substituted or unsubstituted hydrocarbon group having 3 to 20 carbon atoms; and one or two of Y 5, Y 6, and Y 7 each represent a substituted or unsubstituted hydrocarbon group having 3 to 20 carbon atoms, while the others represent hydroxyl groups; and wherein in formula, A 1 to A 3 each independently represent a hydrogen atom or a methyl group; and A 4 represents a hydroxyl group or a carboxyl group. a first electrode comprising a transparent substrate and a transparent conductive film provided on the transparent substrate; a second electrode that faces the first electrode; an oxide semiconductor layer that is provided on the first electrode or the second electrode; an electrolyte that is provided between the first electrode and the second electrode; a photosensitizing dye that is adsorbed to the oxide semiconductor layer; and a co-adsorbent that is adsorbed to the oxide semiconductor layer together with the photosensitizing dye, the photosensitizing dye being a metal complex compound represented by the following formula, characterized in that the co-adsorbent comprising two kinds of organic compounds selected from the group consisting of an organic compound represented by the following formula, an organic compound represented by the following formula, and an organic compound represented by the following formula or comprising an organic compound selected from the organic compounds represented by formulas to and an organic compound represented by the following formula:: wherein in formula, M represents Ru; R 1, R 2, R 3, and R 4 each independently represent a monovalent cation; and R 5 and R 6 each independently represent a halogen group, -H, - CN, -NCS, or -NCO; wherein in formula, n represents an integer from 0 to 5; and R 7 represents a monovalent group having a π-conjugated structure, or a monovalent group having a steroid skeleton; wherein in formula, W represents a carbon atom or a silicon atom; Y 1, Y 2, Y 3, and Y 4 each independently represent a hydrogen atom, a carboxyl group, a substituted or unsubstituted alkoxy group having 1 to 6 carbon atoms, or a substituted or unsubstituted hydrocarbon group having 3 to 20 carbon atoms; and one of Y 1, Y 2, Y 3, and Y 4 represents a substituted or unsubstituted hydrocarbon group having 3 to 20 carbon atoms, while at least two of the remaining groups each represent a carboxyl group or a substituted or unsubstituted alkoxy group having 1 to 6 carbon atoms; wherein in formula, Y 5, Y 6, and Y 7 each independently represent a hydroxyl group or a substituted or unsubstituted hydrocarbon group having 3 to 20 carbon atoms; and one or two of Y 5, Y 6, and Y 7 each represent a substituted or unsubstituted hydrocarbon group having 3 to 20 carbon atoms, while the others represent hydroxyl groups; and wherein in formula, A 1 to A 3 each independently represent a hydrogen atom or a methyl group; and A 4 represents a hydroxyl group or a carboxyl group.