A wavelength aligning apparatus using an arrayed waveguide grating (AWG), and particularly, to a wavelength aligning apparatus using an arrayed waveguide grating which is capable of aligning optical sources using a transmission characteristic of an arrayed waveguide grating in a wavelength alignment method. The apparatus includes a signal generator for applying a signal spaced-apart at a predetermined interval near a predetermined frequency to a bias current of the light source and dithering a central wavelength of each light source, an arrayed waveguide grating for providing a reference wavelength causing a variation difference from the central portion due to a dithering of the central wavelength, a temperature controller for determining a reference wave length by constantly maintaining a temperature of the arrayed waveguide grating, an optical fiber coupler disposed in an output terminal of the arrayed waveguide grating for dividing the signal into a transmission signal and an incoming signal, a plurality of locking amplifiers and a proportional/integration/differentiating unit for computing a bias current corresponding to the detected error signal, and a superposing unit for superposing the computed bias current and a signal from the signal generator for output to the laser diode driver.