A method for producing a halogen-crosslinked iridium dimer represented by the following general formula, comprising reacting an iridium compound represented by the following general formula with an aromatic bidentate ligand represented by the following general formula in a solvent to produce the halogen-crosslinked iridium dimer represented by the following general formula, the solvent having a boiling point of 50°C or higher and lower than 350°C, the aromatic bidentate ligand being added in an amount of 0.5 times or more and less than 10 times the molar amount of the iridium compound, and the reaction of the iridium compound and the aromatic bidentate ligand being carried out at a reaction temperature of 50°C or higher and lower than 300°C, and under normal pressure: wherein Ir represents an iridium atom, O represents an oxygen atom, X represents a halogen atom, and Y represents a counter cation; R 1 to R 6 each independently represent a hydrogen atom, an alkyl group, or an aryl group, and some or all of hydrogen atoms of the alkyl group or aryl group may be substituted with halogen atoms; and adjacent ones of R 1 to R 6 may be linked together to form a ring structure; wherein N represents a nitrogen atom, C represents a carbon atom, H represents a hydrogen atom, CyA represents a five-membered or six-membered cyclic group containing nitrogen atoms, CyB represents a five-membered or six-membered cyclic group containing carbon atoms, and CyA and CyB may be linked together to form a ring structure; and wherein Ir represents an iridium atom, N represents a nitrogen atom, C represents a carbon atom, X represents a halogen atom, CyA represents a five-membered or six-membered cyclic group containing nitrogen atoms, and is linked to iridium via the nitrogen atoms, and CyB represents a five-membered or six-membered cyclic group containing carbon atoms, and is linked to iridium via the carbon atoms; and CyA and CyB may be linked together to further form a ring structure. wherein Ir represents an iridium atom, O represents an oxygen atom, X represents a halogen atom, and Y represents a counter cation; R 1 to R 6 each independently represent a hydrogen atom, an alkyl group, or an aryl group, and some or all of hydrogen atoms of the alkyl group or aryl group may be substituted with halogen atoms; and adjacent ones of R 1 to R 6 may be linked together to form a ring structure; wherein N represents a nitrogen atom, C represents a carbon atom, H represents a hydrogen atom, CyA represents a five-membered or six-membered cyclic group containing nitrogen atoms, CyB represents a five-membered or six-membered cyclic group containing carbon atoms, and CyA and CyB may be linked together to form a ring structure; and wherein Ir represents an iridium atom, N represents a nitrogen atom, C represents a carbon atom, X represents a halogen atom, CyA represents a five-membered or six-membered cyclic group containing nitrogen atoms, and is linked to iridium via the nitrogen atoms, and CyB represents a five-membered or six-membered cyclic group containing carbon atoms, and is linked to iridium via the carbon atoms; and CyA and CyB may be linked together to further form a ring structure.