A polarized wave scrambler and an optical signal transmission apparatus in which polarization mode dispersion is suppressed, and which has first and second polarization maintaining optical fibers, wherein respective constant components of a phase difference characteristic for optical frequencies between high-speed and low-speed axes of the first and the second polarization maintaining optical fibers are equal, and respective slopes for optical frequencies of the phase difference characteristics of the first and second polarization maintaining optical fibers are different. A plane of polarization of the linearly polarized optical signal is set to an angle between the high-speed axis and the low-speed axis of the first polarization maintaining optical fiber and the linearly polarized optical signal is supplied to the first polarization maintaining optical fiber. Further, the first and the second polarization maintaining optical fibers are spliced such that the high-speed axis of the first, corresponds to the low-speed axis of the second, polarization maintaining optical fiber, and the low-speed axis of the first, corresponds to the high-speed axis of the second, polarization maintaining optical fiber.