Provided are a Raman amplifier and a Raman pumping method. A light source unit outputs a pumping light having a wavelength that periodically changes. A light intensity control unit varies a light intensity of the pumping light using the pumping light to improve the gain flatness of a Raman gain. A control unit directs the light intensity control unit to control the light intensity of the pumping light in synchronization with changes in the wavelength of the pumping light.