A UV-absorbing filter absorbs a UV component of incoming light to reduce an amount of the UV component of transmitted light. The UV-absorbing filter comprises a transparent UV-absorbing glass plate which contains a UV-absorbing substance; a transparent first and second heat-resistant glass plates which face respective surfaces of the UV-absorbing glass plate; a first and second distance pieces which are made of heat-resistant resin and which are respectively interposed between the UV-absorbing glass plate and the first and second heat-resistant glass plates, in the vicinity of an outer edge of the UV-absorbing glass plate, so as to form a space between them.