CONSTRUCTION MACHINE

A regeneration device (22) that performs regeneration treatment of a particulate matter removing filter (21) estimates a trapping amount of particulate matter trapped in the filter (21) by two systems. Specifically, there are provided an estimating unit that estimates a first estimated trapping amount (Q1) based upon a rotational speed (N) of an engine (10) and a fuel injection quantity (F) and an estimating unit that estimates a second estimated trapping amount (Q2) based upon a differential pressure across the particulate matter removing filter (21). The regeneration device (22) determines whether or not the regeneration treatment is executed based upon whether or not at least one of the two estimated trapping amount (Q1, Q2) is equal to or more than a preset trapping amount threshold value (Qs). Further, the regeneration device (22) determines that there is a malfunction in the regeneration device (22) in a case where the second estimated trapping amount (Q2) is larger than the first estimated trapping amount (Q1).