Provided is a rod lens array that includes: a plurality of lenses; and a pair of side plate sections interposing side surfaces of the respective lenses in between to hold the lenses, and each including a first side plate provided adjacent to the lenses, and a second side plate provided on outer side of the first side plate, and having machinability lower than machinability of the first side plate, and a linear expansion coefficient smaller than linear expansion coefficient of the first side plate.