PURPOSE: To reduce a leakage current and contrive a decrease of a threshold current ad improvement in the efficiency of a semiconductor laser by forming the first semiconductor layer and the second semiconductor layer of the same conductivity type so that they may cover both ends of an active layer before forming a plurality of buried layers.

CONSTITUTION: An InGaAsP active layer 2 and an n-InP clad layer 3 perform an epitaxial growth in sequence on a p-InP substrate 1 and a mesa-stripe struc ture 4 is formed by etching. Then the active layer 2 is selectively etched and a thin p-InP layer 9 is formed so that both ends of the active layer 2 may be covered by causing the p-InP layer to grow for a very short time and its structure allows the first n-InP buried layers 5 to grow. Then its structure allows the second n-InP buried layers 6 to grow and the third n-InGaAsP buried layers 7 to grow. Thus a leakage current decreases and a highly efficient buried semiconductor laser is obtained by a low threshold current.