A method of producing a semiconductor laser device includes the steps of preparing first and second substrate products each of which includes a substrate and a stacked semiconductor layer formed on the substrate, the first and second substrate products being different from each other; etching the first substrate product with a chlorine-based gas in a vacuum chamber by using a dry etching method; evacuating the vacuum chamber while monitoring a partial pressure of hydrogen chloride in the vacuum chamber so as to obtain the partial pressure of the hydrogen chloride within a predetermined range; after evacuating the vacuum chamber, introducing the second substrate product into the vacuum chamber while maintaining a vacuum state inside the vacuum chamber; and etching the second substrate product with a chlorine-based gas in the vacuum chamber by using the dry etching method.