A semiconductor light emitting device having good characteristics, high reliability and long lifetime includes a p-n junction or p-i-n junction made by locating an active layer in a position inside an n-type doped layer or p-type doped layer sufficiently distant from the depletion layer between the p-type doped layer and the n-type doped layer. When a component of intensity of light from the active layer normal to the active layer is P(x), x for its maximum value Pmax is x=0, and the range of x satisfying P(x)>Pmax/e2 is −Ln −Ln is made lower than doping concentration of the other portion of the n-type doped layer, or doping concentration of at least a part of the p-type doped layer where x