The present invention relates to a vehicle air conditioner having a photocatalyst module, i.e., a two-layered flow air conditioner in which an inner flow path of the air conditioner is divided into an upper flow path and a lower flow path, the air conditioner providing an optimal design location and a mounting structure of a photocatalyst module which are capable of purifying both the upper flow path and the lower flow path by using a minimum number of photocatalyst modules.