The present invention relates to an oral fast-dissolving formulation which not only increases dissolvability of blonanserin to water, but also rapidly dissolves blonanserin in mouth. The oral fast-dissolving formulation comprises blonanserin and salts thereof having average particle size of 1-10 &mum, an acidic pH adjustor, and a pharmaceutically acceptable additive.COPYRIGHT KIPO 2016본 발명은 블로난세린의 물에 대한 용해도를 향상시킬 뿐만 아니라 구강에서 신속하게 붕해시킬 수 있는 구강 속분해성 제제에 관한 것이다.