Abstract: An organic semiconductor laser device is composed of a positive electrode layer, an electron hole-transporting layer, a light-emitting layer containing an organic dye and having an open end, an electron-transporting layer, and a negative electrode layer in order. The electron hole-transporting layer and the electron-transporting layer satisfy the conditions of 1<n1/n2 and 1<n1/n3 (n1 is a refractive index of the light-emitting layer determined at a wavelength of the light emitted in the light-emitting layer, n2 is that of the electron hole-transporting layer, and n3 is that of the electron-transporting layer) and further satisfy the conditions; 0.