Rotary-drum laundry dryer (1) comprising an outer casing (2) having a front wall (2a) and a rear wall (2b), a rotatable drum (3) which is structured for housing the laundry to be dried and is fixed in axially rotating manner inside the casing (2), and a hot-air generator (6) structured to circulate a stream of hot air through the rotatable drum (3); said rotatable drum (3) comprising a substantially cylindrical, tubular body (3) having its front rim (3f) coupled in axially rotating manner to the front wall (2a) of the casing (2) and its rear rim (3r) coupled in substantially airtight and axially rotating manner to the rear wall (2b) of the casing (2) with the interposition of a rear circular sealing gasket (10); the rotary-drum laundry dryer (1) being characterized in that said substantially cylindrical, tubular body (3) is structured for resting on a number of idle supporting rollers (8) which are arranged approximately at the two axial ends of the tubular body (3) so as to allow the tubular body (3) to rotate about its longitudinal reference axis (L) inside the casing (2), and the rear wall (2b) of the casing (2) comprises: a substantially vertically-oriented supporting bulkhead (14) which is made of plastic material and has a permeable-to-air central portion (14c) which is aligned/faced to the rear mouth of the tubular body (3) delimited by said rear rim (3r); a lid or cover (18) which is fixed in substantially airtight manner to the outer face of the supporting bulkhead (14) immediately above said permeable-to-air central portion (14c) of the supporting bulkhead (14), and is shaped so as to form, together with said supporting bulkhead (14), an inner cavity (19) which is fluidly connected to the hot-air generator (6) and to the inside of said tubular body (3); and a substantially cylindrical gasket-supporting collar (16) which protrudes from the inner face of the supporting bulkhead (14) towards the tubular body (3) while remaining substantially coaxial to the rear rim (3r) of said tubular body (3), and has a nominal diameter greater than that of the rear rim (3r) of the tubular body (3); the rear circular sealing gasket (10) being firmly fixed in abutment against the gasket-supporting collar (16) and the gasket-supporting collar (16) being realized in one piece with said supporting bulkhead (14).