To provide a wavelength dispersion compensation device dispensing with an optical circulator.

Light from a single-mode fiber 12a is emitted as collimated light from a two-core collimator 21 and made incident on a polarizing prism 22. The collimated light emitted from the polarizing prism 22 is vertically made incident on nearly half the plane side area of a line focus lens 14, and then, reflected by a free-curved mirror 17 after passing through the line focus lens 14, a VIPA element 15 and nearly half the area of a focus lens 16, then, the wavelength dispersion is compensated, thereafter, the light passes through the remaining area through which the light emitted from the single mode fiber 12a does not pass, and then, the light is made incident on the two-core collimator 21 as the collimated light. The collimated light made incident on the two-core collimator 21 is converged by a collimating lens 13, and then, made incident on a single mode fiber 12b.