A package substrate according to an embodiment of the present invention comprises: at least a conductor circuit and an insulating layer formed and laminated to form a laminated body; at least one solder resist layer further formed and laminated on both sides of the laminated body; an optical element; and an optical path for transmitting an optical signal, wherein at least one outermost layer of the solder resist layers formed and laminated on the laminated body has a transmittance for light having a wavelength for communication of about 60% or more at a thickness of 30 μm.