Compressed air supply unit for operating a pneumatic unit by means of a compressed air flow, in particular for operating an air suspension unit of a vehicle, preferably a passenger car, having: - an air dryer arrangement in a main pneumatic line that pneumatically links a compressed air feed from an air compressor and a compressed air connection leading to the pneumatic unit, and - a valve arrangement, pneumatically connected to the main pneumatic line, for controlling the compressed air flow, wherein - the air dryer arrangement has a drying container having a container outer wall, wherein - a partition along a longitudinal extent of the drying container divides an internal space delimited by the container outer wall into a first and a second chamber (151, 152), wherein the first chamber and the second chamber are delimited by the partition and the container outer wall, and - the partition adjoins the container outer wall along the longitudinal extent, and the first chamber and the second chamber are arranged adjacent to one another along the longitudinal extent, characterized in that - a pneumatic link links the first chamber to the second chamber, wherein - the compressed air flow in the first chamber and the second chamber can be routed in opposite directions and along the longitudinal extent and can be routed transversely to the longitudinal extent in the pneumatic link, wherein the first and second chambers (151, 152) in the drying container are pneumatically linked by just a single passage to form the pneumatic link within the drying container in order to form a series circuit of a first and a second air dryer stage (101, 102) of the air dryer arrangement in the main pneumatic line. - an air dryer arrangement in a main pneumatic line that pneumatically links a compressed air feed from an air compressor and a compressed air connection leading to the pneumatic unit, and - a valve arrangement, pneumatically connected to the main pneumatic line, for controlling the compressed air flow, wherein - the air dryer arrangement has a drying container having a container outer wall, wherein - a partition along a longitudinal extent of the drying container divides an internal space delimited by the container outer wall into a first and a second chamber (151, 152), wherein the first chamber and the second chamber are delimited by the partition and the container outer wall, and - the partition adjoins the container outer wall along the longitudinal extent, and the first chamber and the second chamber are arranged adjacent to one another along the longitudinal extent, characterized in that - a pneumatic link links the first chamber to the second chamber, wherein - the compressed air flow in the first chamber and the second chamber can be routed in opposite directions and along the longitudinal extent and can be routed transversely to the longitudinal extent in the pneumatic link, wherein the first and second chambers (151, 152) in the drying container are pneumatically linked by just a single passage to form the pneumatic link within the drying container in order to form a series circuit of a first and a second air dryer stage (101, 102) of the air dryer arrangement in the main pneumatic line.