An object of the present invention is to provide a moving body side section structure capable of correcting a flow of fluid on the upper portion of a moving body and improving stability of the moving body. In a moving body side section structure that includes a flow correction fin 1A that is provided on a side section of a moving body and corrects a flow of fluid of the side section of the moving body, the length of the flow correction fin 1A in a longitudinal direction of the moving body is set so as to be longer than the length of the fin in a vertical direction of the moving body, the flow correction fin includes a first inclined portion 1Ae which is formed at a front end portion in the longitudinal direction of the moving body and in which a width in a width direction of the moving body is widened toward a rear side in the longitudinal direction of the moving body, and a second inclined portion 1Af which is formed further rearward than the first inclined portion 1Ae in the longitudinal direction of the moving body and in which the width in the width direction of the moving body is narrowed toward the rear side in the longitudinal direction of the moving body, a ridge line 1Ab that connects a front end portion and a rear end portion in the longitudinal direction of the moving body is provided, and an inflection portion 1Ac that discontinuously narrows the width in the width direction of the moving body in the rear end portion may be set.