Disclosed is a metal complex which has a central metal (M) selected from the group consisting of Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, Hf, Ta, W, Re, Pt, Au and Hg. The metal complex has no halogen unidentate ligand. In the metal complex, the sum total of the square values of the orbital coefficients of the outermost d orbitals of the central metal comprises 1/3 or higher of the sum total of the square values of all of the atomic orbital coefficients in the highest occupied molecular orbital (HOMO) given by a computational scientific technique, the energy difference (S1-T1) between the minimum singlet excitation energy (S1) and the minimum triplet excitation energy (T1) given by a computational scientific technique falls within the range from 0.1 (eV) to 1.0 (eV) inclusive, and the oscillator strength (f) falls within the range from 0.005 and 1.0 inclusive.