The present invention describes a planar waveguide-type integrated non-reciprocal polarization rotator. According to an embodiment of the present invention, the planar waveguide-type non-reciprocal 90° polarization rotator includes optical waveguide-type input and output ports, a reciprocal 45° polarization rotator based on an asymmetric optical waveguide structure, a non-reciprocal 45° polarization rotator based on an optical waveguide with a clad layer of magneto-optic material, and a phase compensator placed between the above reciprocal 45° polarization rotator and non-reciprocal 45° polarization rotator compensating the phase difference between two polarization modes.