NOVELTY - A solar cell apparatus (1) has solar cell element (13), electrodes (12a,12b), and variable beam condensing unit (20). The condensing unit has a translucent support (21) having a hydrophilic photocatalyst (S), and translucent liquid (L1). The hydrophilic photocatalyst is titania, barium titanate, strontium titanate, barium zirconate, strontium zirconate, or germanium nitride, optionally doped with nitrogen, sulfur or carbon. When light (R2) of preset wavelength is irradiated, hydrophilicity increases to more than that when light is not irradiated.    USE - Solar cell apparatus. Uses include but are not limited to mobile components, solar cars, photovoltaic power generation type roofing tiles, and outdoor power supply.    ADVANTAGE - The solar cell apparatus has a simple structure which reduces dependence of light collecting efficiency on light incoming angle, and improved power generation efficiency.    DETAILED DESCRIPTION - A solar cell apparatus consists of a solar cell element, a pair of electrodes connected to the solar cell element, and a variable beam condensing unit arranged facing the solar cell element. The variable beam condensing unit consists of a translucent support having a hydrophilic photocatalyst on the surface, and translucent liquid (L1) supported in contact with the surface of the translucent support. The hydrophilic photocatalyst is titania, barium titanate, strontium titanate, barium zirconate, strontium zirconate, or germanium nitride, optionally doped with nitrogen, sulfur or carbon. When light of preset wavelength is irradiated, hydrophilicity increases to more than that when light is not irradiated. Translucent liquid (L1) is water or an aqueous solution. A condensing lens is not formed when light is irradiated to the hydrophilic photocatalyst above a preset luminous flux density. A condensing lens is formed when light is irradiated to the hydrophilic photocatalyst with less than a preset luminous flux density. An INDEPENDENT CLAIM is included for condensing method.    DESCRIPTION OF DRAWING(S) - The drawing shows a sectional view of the solar cell apparatus.    Solar cell apparatus (1)    Electrodes (12a,12b)    Solar cell element (13)    Variable beam condensing unit (20)    Translucent support (21)    Translucent liquids (L1,L2)    Light (R2)    Hydrophilic photocatalyst (S)