There is provided an ultraviolet absorber having a strong absorptive capacity in the UVA range and an absorptive capacity in the UVB range to have an ultraviolet inhibitory effect in a wide range of wavelength, increasing in an ultraviolet absorptive capacity over the course of ultraviolet irradiation time in both the UVA and the UVB ranges and having an excellent solubility. An ultraviolet absorber comprising, as an active ingredient, a compound of General Formula I: (where -OA is an alkoxy group) that exhibits an ultraviolet A wave absorptive capacity which increases over time and that has an ultraviolet B wave absorptive capacity.