Regeneration of particulate filter

A regeneration device for a filter (13) which traps particulate matter in an exhaust gas of an engine (1) is disclosed. A sensor (25) detects an engine running point. A controller (22) determines whether or not the detected engine running point is in a low load region, when the deposition amount of particulate matter is more than a first reference amount (PMn). Further, the controller (22) immediately starts a first filter regeneration control by raising a temperature of the exhaust gas, when the detected engine running point is not in the low load region, and starts a second filter regeneration control by raising the temperature of the exhaust gas after the deposition amount of particulate matter exceeds a second reference amount (PMe), when the detected engine running point is in the low load region.