Abstract: The invention relates to an incinerator apparatus, comprising a primary combustion chamber (12), means for heating the primary combustion chamber (12), a secondary combustion chamber (14) communicating with the primary combustion chamber (12), and afterburner means opening out into the secondary combustion chamber (14) and through which the combustion gases from the primary combustion chamber (12) are caused to pass when entering into the secondary combustion chamber (14). Between the primary combustion chamber (12) and said afterburner means there is arranged a mixing chamber 13 extending along one long side of the primary combustion chamber (12) and communicating therewith via a venting gap (23), adjustable in height and formed between the upper part (8) of the primary combustion chamber (12) and the upper edge of a partial partition wall (11), which separates the primary combustion chamber (12) from the mixing chamber (13).