An exhaust gas control system for an internal combustion engine (1), before execution of a filter regeneration process, executes a pre-regeneration process that is a process of raising a temperature of a filter (50a) to a second target temperature lower than a first target temperature and increasing the concentration of NO 2 contained in exhaust gas flowing into the filter (50a) for a predetermined period. An execution time of the filter regeneration process when a physical quantity that correlates with a speed of change in a detected value of a differential pressure sensor (53) during execution of the pre-regeneration process is large is shorter than an execution time of the filter regeneration process when the physical quantity is small.