We investigate the boson star with the self-interacting scalar field as a model of galactic halos. The model has slightly increasing rotation curves and allows wider ranges of the mass($m$) and coupling($λ$) of the halo dark matter particle than the non-interacting model previously suggested(ref.\cite{sin1}). Two quantities are related by $λ^{\frac{1}{2}} (m_p/m)^2\st{>}{\sim} 10^{50}$.

15 pages. Standard Latex file with 2 tex figures. Revised version to be published in Phy. Rev. D. (Stability arguments are added.)