A catalyst including, as effective ingredient, complex represented by Formula (1) which contains bidentate ligand including aromatic heterocyclic 5-membered ring having 2 or more nitrogen atoms, or represented by Formula (2) which contains bidentate ligand including: aromatic heterocyclic 5-membered ring having 2 or more nitrogen atoms; and 6-membered ring having 1 or more nitrogen atoms, isomer or salt of the complex: where M 1 and M 2 denote transition metal such as iridium; X 1 to X 16 each independently denote nitrogen or carbon; R 1 to R 13 denote, for example, hydrogen atom, alkyl group, or hydroxy group, provided that when X i (where i denotes 13 to 16) is nitrogen, R i is absent at position corresponding to the nitrogen; L 1 and L 2 denote, for example, an aromatic anionic ligand; Z 1 and Z 2 denote any ligand or are absent; and m and n denote positive integer, 0, or negative integer.