A regeneration control device which regenerates a filter (13) by increasing an exhaust gas temperature to burn exhaust gas particulates trapped in the filter, is disclosed. The filter (13) traps particulate matter in exhaust gas from an engine (1). The regeneration control device suppresses fuel cost-performance impairment due to filter regeneration. The regeneration control device has a load detection sensor (31) which detects an engine load and a microcomputer-based controller (22). The controller is programmed to perform engine control to adjust the exhaust gas temperature for regeneration of the filter (13), when a computed trapped amount is equal to or more than the first reference value (A) and less than the second reference value (B), and the detected load (Vsp) is equal to or more than a reference load (Vo); and perform engine control to adjust the exhaust gas temperature for regeneration of the filter (13) regardless of the detected load (Vsp), when the computed trapped amount is equal to or more than the second reference value (B).