We described morphological characteristics of embryonic, larval, and juvenile period of the yellow puffer, Takifugu obscurus. We defined seven periods of embryogenesis the zygote, cleavage, blastula, gastrula, segmentation, pharygula, and hatching periods. The eggs were adhesive and spherical in shape. The egg yolk had numerous tiny oil globules. Hatching began about 280 hours after insemination at $17.0{pm}1.0^{circ}C$ water temperature. Melanopores of star shape were seen on yolk, head and trunk during the pharygula and hatching period. The hatched larvae haying large yolk were $3.00~3.54$ mm in size with $25~26$ myomeres. The larvae completely absorbed the yolk materials and oil globules within 7 days after hatching and became post-larvae. Laval fish became juveniles within 60 days after hatching, and they reached $23.54~30.12$ mm in total length and had fin-rays.