Provided are a non-reciprocal unit used for a polarization dependent type optical isolator and a polarization dependent type optical isolator that are simple in structure, can prevent damages due to light and heat and can obtain a high extinction ratio. In a polarization dependent type optical isolator, an input side lens (first lens) (5), a first birefringence unit (7), a Faraday rotator (9), a second birefringence unit (11) and an output side lens (second lens) (15) are arranged from the input side to the output side. The polarization dependent type optical isolator (1) is connected with optical fibers (3, 17) on the input and output sides, respectively, wherein a wedge angle (θ1) of the first birefringence unit (7) is different from a wedge angle (θ2) of the second birefringence unit (11).