A semiconductor laser diode includes a semiconductor substrate, an active layer having a double hetero structure formed on the semiconductor substrate, a first quantum well layer formed between the active layer and the current confinement layer, a second quantum well layer formed on the active layer corresponding to the current injection groove, and a clad layer having its flat surface formed on the current injection groove and the current confinement layer. A method for manufacturing the semiconductor laser diode includes the steps of forming an active layer having a double hetero structure on the semiconductor substrate, selectively forming a current confinement layer on the active layer to form a current injection groove, forming a clad layer having its flat surface on the current injection groove and the current confinement layer.