A surface light source apparatus with dual-side emitting light includes a transparent cathode structure, a transparent anode structure, a fluorescent layer and a low-pressure gas layer. The transparent cathode structure and the transparent anode structure are opposite to each other and respectively a surface structure. The fluorescent layer is located between the transparent cathode structure and the transparent anode structure. The low-pressure gas layer fills a space between the transparent cathode structure and the transparent anode structure and functions to induce the cathode for evenly emitting electrons. In addition, the electron mean free path of the low-pressure gas layer allows at least sufficient electrons to directly impact the fluorescent layer under an operation voltage.