Abstract: A pyrolysis device (1; 200) comprising an elongated tubular structure (2; 201) which extends along a longitudinal axis (X) and includes a first tubular body (3; 202) which defines an initial washing or drainage chamber, in which a shaped carriage (5; 204) containing a polymeric material to be subjected to pyrolysis thermal treatment is received, and provided with a movable front shutter (8; 207), arranged at an axial inlet mouth (9) through which the shaped carriage (5; 204) is introduced into the initial chamber (4; 203), and cooperating with first actuating means (10; 209) which alternately move them at least between a first position, in which the front shutter (8; 207) closes the initial chamber (4; 203) from the outer side (4a), and a second position, in which the front shutter (8; 207) opens the initial chamber (4; 203) from such an outer side (4a) putting it into communication with the external environment.