Air conditioning device for conditioning the air present in an inner environment of a means of transport, said device comprising: - a fluidic circuit configured to circulate a first operative fluid; - conditioning means cooperating, in use, with the circuit to condition the first operative fluid and, through this, the air present in the inner environment of the means of transport; and - a radiator mass configured to receive a second operative fluid and defining a heat exchange interface between the second operative fluid received and the air that laps/crosses, in use, the radiator mass; wherein the air conditioning device is of modular type and the conditioning means and the radiator mass are housed in respective, separate casings (5, 7) connectable in a releasable manner to one another directly or with interposition of parts; wherein the air conditioning device comprises: - a first casing housing the conditioning means, defining a first module of the device, having a first inlet opening for the air to be conditioned and a first outlet opening for the conditioned air; and - a second casing housing the radiator mass, defining a second module of the device, having a second inlet opening for the air and a second outlet opening for the air; characterized in that the first casing includes a first connection interface arranged at the first outlet opening, in that the second casing includes a second connection interface arranged at the second inlet opening, and in that said first connection interface is couplable to said second connection interface by means of releasable fastening means, directly or with interposition of parts. - a fluidic circuit configured to circulate a first operative fluid; - conditioning means cooperating, in use, with the circuit to condition the first operative fluid and, through this, the air present in the inner environment of the means of transport; and - a radiator mass configured to receive a second operative fluid and defining a heat exchange interface between the second operative fluid received and the air that laps/crosses, in use, the radiator mass; wherein the air conditioning device is of modular type and the conditioning means and the radiator mass are housed in respective, separate casings (5, 7) connectable in a releasable manner to one another directly or with interposition of parts; wherein the air conditioning device comprises: - a first casing housing the conditioning means, defining a first module of the device, having a first inlet opening for the air to be conditioned and a first outlet opening for the conditioned air; and - a second casing housing the radiator mass, defining a second module of the device, having a second inlet opening for the air and a second outlet opening for the air; - a first casing housing the conditioning means, defining a first module of the device, having a first inlet opening for the air to be conditioned and a first outlet opening for the conditioned air; and - a second casing housing the radiator mass, defining a second module of the device, having a second inlet opening for the air and a second outlet opening for the air; characterized in that the first casing includes a first connection interface arranged at the first outlet opening, in that the second casing includes a second connection interface arranged at the second inlet opening, and in that said first connection interface is couplable to said second connection interface by means of releasable fastening means, directly or with interposition of parts.