Vehicle air conditioning system

A vehicle air conditioning system includes: an air conditioning duct through which air can flow; an evaporator disposed in the air conditioning duct; and a humidity control device disposed on an upstream side of the evaporator in the air conditioning duct. The humidity control device includes: a honeycomb structure having an outer peripheral wall and partition walls disposed on an inner side of the outer peripheral wall, the partition walls defining a plurality of cells, each of the cells extending from a first end face to a second end face to form a flow path, at least the partition walls being made of a material having a PTC property; and a dehumidifying layer formed on a surface of each of the partition walls.