Adequate vitamin $B_2$, vitamin $B_6$, folate and vitamin $B_{12}$ intakes are known to be important for the growth and development in infants. The purpose of this study was to evaluate concentrations of vitamin $B_2$, vitamin $B_6$, folate and vitamin $B_{12}$ in human milk and to investigate the relationship between vitamin B levels in human milk and dietary habits and other health-related behaviors. Milk samples were obtained from 38 healthy lactating women (aged 29.0 $pm$ 3.2 years) who are participating in the cohort study on pregnant women. Vitamin $B_2$ concentrations in human milk were positively correlated with maternal vitamin $B_2$ intakes in lactating mothers. Vitamin $B_6$, folate and vitamin $B_{12}$ concentrations in human milk were not correlated with maternal B vitamin intakes. Vitamin $B_6$ concentrations in human milk were negatively correlated with the amount of postpartum weight loss. The vitamin B concentrations in human milk were not associated with maternal age, height, weight and parity. Mothers who were exposed to indirect smoking had lower vitamin $B_2$ concentrations, and those who reported to consume health foods had higher vitamin $B_2$ concentrations in their milk. In conclusion, lactating women need to consume more vitamin B intakes for the growth and development in infants. Further researches are needed to find other diet and health-related factors which influence on B vitamin concentrations in human milk.