Objectives The purpose of this study is to evaluate the effect of hot spring bath in obese children. Methods The study was conducted with 20 obese children whose BMI were over 20 ($kg/m^2$). The hot spring bath program was performed in the hot-spring facilities with temperature of $32{sim}36^{circ}C$. The children bathed four times from June to July, 2012. Prior to their bath, their heights, weights, and body compositions were measured every time. They were also confirmed their obesity index and obesity degree during the program. Results After the bathing program, degree of obesity has changed, three obesity judgment index (BMI, RI and OI) of the children have decreased (BMI, RI, OI on the $1^{st}$ day: $25.99{pm}3.47$, $177.63{pm}17.43$, $37.74{pm}13.42$; on the $4^{th}$ day: $25.06{pm}3.08$, $168.4{pm}14.8$, $30.60{pm}12.12$), so have body fat mass and percent body fat (BFM, PBF on the $1^{st}$ day: $21.83{pm}7.03$, $38.24{pm}3.36$; on the $4^{th}$ day:$19.55{pm}6.35$, $34.20{pm}3.77$), but skeletal muscle mass has increased (SMM on the $1^{st}$ day: $18.37{pm}4.24$ ; on the $4^{th}$ day: $19.80{pm}4.44$). Conclusions This study shows that hot spring bath could be an effective way of managing and treating obesity.