To provide a vehicular air conditioning system that can enhance convenience of an occupant.

An air conditioning system includes a device switchable between the states that the inside of a cabin is and is not partitioned into a forward space and a rear space, a forward side air conditioner for sending air to a forward space and rear side air conditioner for sending air to a rear space, wherein a control device 50 for the system includes a dew condensation prevention control execution part 102 for preventing the production of dew condensation through the intake of air from the rear space by the rear side air conditioner, a quick appropriate-temperature control execution part 104 for operating forward side air conditioner and rear side air conditioner in an unpartitioned state to quickly make temperature in the rear spaces appropriate temperature, and a thawing control execution part 106 for thawing icing to the front window in a partitioned state. By so doing, it is possible to prevent the occurrence of dew condensation of the rear space, to secure comfortability of the rear space and to quickly thaw the front window. As a result, comfortability of an occupant can be enhanced.