A package substrate includes a laminated body having a conductor circuit and an insulating layer formed and laminated, solder resist layers formed and laminated on both sides of the laminated body, respectively, an optical element, and an optical path for transmitting an optical signal. One or more of the solder resist layers formed and laminated on the laminated body is an outermost layer which has a transmittance for light having a wavelength for communication of about 60% or more at a thickness of 30 μm.