An internal combustion engine exhaust emission control system provided with a filter provided on an internal combustion engine exhaust path to collect PMs in exhaust, wherein a technology is provided that can more properly prevent a filter temperature from excessively rising during the execution of a filter regenerating control. When, during the execution of a filter regenerating control, a suction air volume in an internal combustion engine is reduced to a level that potentially causes an excessive filter temperature rise, the oxygen concentration of atmosphere around the filter is reduced to a target oxygen concentration. If a reduced suction air volume is larger than a certain level, a reducing agent is supplied to a catalyst mostly provided upstream the filter or supported on the filter to thereby reduce the oxygen concentration of atmosphere around the filter (S106). If a reduced suction air volume is up to a certain level, an exhaust throttle valve is mostly used to throttle exhaust to thereby reduce the oxygen concentration of atmosphere around the filter (S104).