A method for producing an integrated optical device includes the steps of growing, on a substrate including first and second regions, a first stacked semiconductor layer, a first cladding layer, and a side-etching layer; etching the first stacked semiconductor layer through a first etching mask formed on the first region; selectively growing, on the second region, a second stacked semiconductor layer and a second cladding layer; growing a third cladding layer and a contact layer on the first and second stacked semiconductor layers; and forming a ridge structure. The step of etching the first stacked semiconductor layer includes a step of forming an overhang between the first cladding layer and the first etching mask. The step of forming a ridge structure includes first, second, and third wet-etching steps in which the third cladding layer, the side-etching layer and the first and second cladding layers are selectively etched, respectively.