A PMD emulator configured by connecting in this order: an input-side optical fiber 71 for receiving light to be measured; a first polarization rotating portion 73 including M DGD sections 76 (M is an integer equal to or more than 2) concatenated by (M-1) polarization rotators 80, one DGD section being arranged at each end of said first polarization rotating portion; an arbitrary-arbitrary polarization controller 75 for changing any state of polarization into any other state of polarization, a second PMD rotating portion 74 configured in the same way as the first polarization rotating portion 73 an output-side optical fiber for outputting the light to be measured.