Abstract: This invention provides a photosetting resin composition suitable as a coating material for optical transmission glass fibers. Owing to the inclusion of a urethane-modified (meth)acrylate and a monoacrylate represented by the following general formula [I]:CH.sub.2 .dbd.CHCO(OC.sub.2 H.sub.4).sub.n OCH.sub.2 CH(C.sub.2 H.sub.5)(CH.sub.2).sub.3 CH.sub.3 [I]wherein n stands for an integer of 1-8, the photosetting resin composition enjoys a high photosetting speed and permits the formation of a coating film of a low modulus of elasticity. Moroever, the modulus of elasticity of the coating film has small temperature dependency at low temperatures. The present invention can hence provide light-transmitting glass fibers having excellent characteristics in optical transmission. The preferred monomer has been identified in the resin parts as 2-ethyl hexoxy ethyl acrylate, and also as 2-(2-ethylhexoxy) ethyl acrylate, and further as 2-[(2-ethylhexyl)oxy]ethyl acrylate.