High performance and high reliability of a semiconductor laser device having a buried-hetero structure are achieved. The semiconductor laser device having a buried-hetero structure is manufactured by burying both sides of a mesa structure by a Ru-doped InGaP wide-gap layer and subsequently by a Ru-doped InGaP graded layer whose composition is graded from InGaP to InP, and then, by a Ru-doped InP layer. By providing the Ru-doped InGaP graded layer between the Ru-doped InGaP wide-gap layer and the Ru-doped InP layer, the Ru-doped InGaP wide-gap layer and the Ru-doped InP layer not lattice-matching with each other can be formed as a buried layer with excellent crystallinity.