Disclosed is an organic-inorganic composite body having a very high hardness on the surface and an adequate hardness in the interior and on the back surface while having excellent adhesion to a substrate. Specifically disclosed is an organic-inorganic composite body mainly comprising a) a condensate of an organosilicon compound represented by Formula (I): R.sub.nSiX.sub.4-n, (wherein R represents an organic group having a carbon atom directly bonded to Si, and X represents a hydroxy group or a hydrolyzable group; n represents 1 or 2, with the proviso that when n is 2, each R may be the same or different, and when (4-n) is 2 or more, each X may be the same or different) and further comprising b) at least one photosensitive compound sensitive to light having a wavelength of 350 nm or less selected from the group consisting of metal chelate compounds, metal-organic acid salt compounds, metal compounds having 2 or more hydroxy groups or hydrolyzable groups, hydrolysates thereof, and condensates thereof; and/or a compound derived from the photosensitive compound, and c) a cured product of an ultraviolet-curable compound.