According to the present invention, there is provided a method of manufacturing a light-transmitting member for an image reading apparatus configured to read an image on a conveyed original, the method including: disposing a plurality of substrates each having a first light-transmitting surface and a second light-transmitting surface opposed to each other so that a part of the first light-transmitting surface of one of two adjacent substrates is in contact with a part of the second light-transmitting surface of another of the two adjacent substrates; and providing coating on the first light-transmitting surface of each of the plurality of substrates.