The invention provides a two-wavelength semiconductor laser device with optimized knee level, working voltage, temperature characteristic and horizontal spread angle. The semiconductor laser device has a first light emitting portion and a second light emitting portion having a longer emission wavelength than that of the first light emitting portion. Each of the first light emitting portion and the second light emitting portion has a stripe-shaped ridge structure used for carrier injection. The ridge structure in the first light emitting portion includes a first front end region having a width Wf1 and having a length L3 from a front facet, a first rear end region having a width Wr1 and having a length L1 from a rear facet, and a first tapered region located between the first front end region and the first rear end region and having a length L2, and the relation of Wf1>Wr1 is satisfied. The ridge structure in the second light emitting portion includes a second front end region having a width Wf2 and having a length L6 from a front facet, a second rear end region having a width Wr2 and having a length L4 from a rear facet, and a second tapered region located between the second front end region and the second rear end region and having a length L5, and the relation of Wf2>Wr2 is satisfied. The relations of L1+L2+L3=L4+L5+L6, Wf1L4 are also satisfied.