|Metal concentrations in river water are said to increase in rainy weather due to runoff and suspended sediment production. A previous study also indicated that it is important to measure the labile metals considering the effect of metals on aquatic ecosystems, but only a few attempts have been made to survey the occurrence and speciation of metals in the rainy river. This study investigated the concentrations of the total and labile metals in the Koise River during rain events (2019/11~2019/12). As a result, total metal concentrations tended to increase with the increase of SS concentration. Particularly, Al, Fe, and Mn concentrations were significantly correlated with the SS concentration. The concentrations of Al, Fe and Ti were 5.9, 4.8, and 0.3 mg/L, respectively when the SS concentration was approximately 200 mg/L. On the other hand, there was no clear relationship between the labile phase concentrations with the SS concentration. These results suggested that, for river water during rain events, the SS concentration is useful to predict the concentrations of total metals while it may be difficult to predict those of the labile phase with them. It was indicated that field surveys are important for understanding metals speciation in a rainy river.