To provide a waste wood carbonization installation which can easily treat waste woods such as plywood for concrete formworks into values below legal standard values in a short time.

The waste woods, plywood for concrete formworks, are charged into a carbonization oven 12. The charged plywood for the concrete formworks is carbonized in the carbonization oven 12 at an ignition point of 800°C. The carbonization of the plywood for the concrete formworks is completed in the carbonization oven 12 for 20 to 30 hr. Steam and smoke during the operation are introduced into a cyclone 14 and cooled with a cooling pipe 78 in the cyclone 14 to separate and collect a pyroligneous acid solution from the smoke. The smoke passed through the cyclone 14 is introduced into a secondary burning oven and stayed and burnt for ≥2 seconds to perfectly decompose dioxins in the smoke.