A shaft connection structure connects a pair of rotating shafts by a fit between a pair of spline shafts, wherein the pair of rotating shafts are provided with corresponding ones of the pair of spline shafts. The shaft connection structure includes a shaft connection assist device. The shaft connection assist device includes a centering ring and centering pins. The centering ring is arranged outside of a first one of the spline shafts and coaxially with the first spline shaft. The centering pins are provided outside of a second one of the spline shafts. The centering pins engage with an outer peripheral surface of the centering ring and bring a shaft axis of the first spline shaft and a shaft axis of the second spline shaft into a range enabling the fit therebetween.