The present invention is a bodyshell structure of a railcar, the bodyshell structure including a plurality of side window opening portions formed on a side bodyshell along a railcar longitudinal direction, and the side window opening portions include a plurality of large window opening portions arranged on a railcar-longitudinal-direction center portion of the side bodyshell and a plurality of small window opening portions arranged on both railcar-longitudinal-direction sides of the large window opening portions and each having a smaller opening area than the large window opening portion.
