We study the optical wavelength dependence of the Brillouin gain spectrum for a silica single-mode fiber in the range from 1511 to 1555 nm using a measurement setup containing an erbium-doped fiber amplifier (EDFA) in the Brillouin pump path. The Brillouin peak power and linewidth are clearly dependent on the pump wavelength, the trends of which correspond well with the wavelength dependence of the EDFA gain. This result suggests that we need to consider the unique wavelength dependence of the EDFA gain to practically obtain a higher Brillouin peak power and narrower linewidth at the telecommunication wavelength.