An emitting layer of an organic electroluminescence device comprising a first material and a second material, wherein the second material is a fluorescent material, the first material is a host material, the second material is a dopant material, singlet energy EgS(H) of the first material and singlet energy EgS(D) of the second material satisfy a relationship of the formula : [Formula 1] EgS H > EgS D characterized in that the first material satisfies a relationship of a formula below in terms of a difference ΔST(H) between the singlet energy EgS(H) and an energy gap Eg 77K (H) at 77K: [Formula 2] Δ ⁢ ST H = EgS H − Eg 77 ⁢ K H < 0.3 eV the first material exhibits thermally activated delayed fluorescence, and a difference ΔT between the energy gap Eg 77K (H) at 77K of the first material and an energy gap Eg 77K (D) at 77K of the second material satisfies a relationship of a formula below: [Formula 3] Δ ⁢ T = Eg 77 ⁢ K H − Eg 77 ⁢ K D ≥ 0.6 eV wherein the singlet energy EgS(H) of the first material and singlet energy EgS(D) of the second material are energy values obtained by a conversion equation below EgS eV = 1239.85 / λ ⁢ edge wherein: λedge represents a wavelength value (nm), said wavelength value being obtained by evaporating said first or said second material on a quartz substrate to prepare a sample, measuring an absorption spectrum of the sample at a normal temperature , expressing the absorption spectrum in coordinates of which ordinate axis indicates absorbance and of which abscissa axis indicates the wavelength, drawing a tangent to the fall of the absorption spectrum on the long-wavelength side, and thereby obtaining said wavelength value λedge (nm) at an intersection of the tangent and the abscissa axis; and the energy gaps Eg77K(H) and Eg77k(D) are energy values obtained by conversion equations and below, Eg 77 ⁢ K H eV = 1239.85 / λ ⁢ edge Eg 77 ⁢ K D eV = 1239.85 / λ ⁢ edge wherein: λedge represents a wavelength value (nm), said wavelength value being obtained by dissolving the first or the second material, respectively, in a solvent to provide a sample; measuring the phosphorescence spectrum of the sample at 77K to express the phosphorescence spectrum in coordinates of which ordinate axis indicates the phosphorescence intensity and of which the abscissa axis indicates a wavelength; and drawing a tangent to a rise of the phosphorescent spectrum on a short-wavelength side to obtain the wavelength value at an intersection of the tangent and the abscissa axis. λedge represents a wavelength value (nm), said wavelength value being obtained by evaporating said first or said second material on a quartz substrate to prepare a sample, measuring an absorption spectrum of the sample at a normal temperature , expressing the absorption spectrum in coordinates of which ordinate axis indicates absorbance and of which abscissa axis indicates the wavelength, drawing a tangent to the fall of the absorption spectrum on the long-wavelength side, and thereby obtaining said wavelength value λedge (nm) at an intersection of the tangent and the abscissa axis; and λedge represents a wavelength value (nm), said wavelength value being obtained by dissolving the first or the second material, respectively, in a solvent to provide a sample; measuring the phosphorescence spectrum of the sample at 77K to express the phosphorescence spectrum in coordinates of which ordinate axis indicates the phosphorescence intensity and of which the abscissa axis indicates a wavelength; and drawing a tangent to a rise of the phosphorescent spectrum on a short-wavelength side to obtain the wavelength value at an intersection of the tangent and the abscissa axis. <EOS>