Provided are a host material for a blue phosphor, and an organic thin film and an organic light-emitting device including the same. The host material for a blue phosphor is such that a carbazole compound is bonded around a central atom, wherein the central atom is a Group 14 element, and the carbazole compound bonded around the central atom is 3 or 4, wherein the carbazole compound. includes carbazole in which an alkyl group is substituted The host material for a blue phosphor has high triplet energy (ET) and excellent electrical mobility and thermal stability. As a result, the organic thin film, which includes the host material, and the organic light-emitting device, which includes the organic thin film, implement a deep blue color and have excellent luminous efficiency.