A warm-up system for an exhaust gas apparatus includes the exhaust gas apparatus having a turbocharger (6) provided with a turbine (61), a first exhaust gas control catalyst (51) provided downstream of the turbine, a bypass passage (52) bypassing the turbine, and an adjustment unit (53, 54; 56) adjusting a turbine inflow exhaust gas flow rate and an electronic control unit (10). The electronic control unit (10) is configured to perform a warm-up control which warms the turbine by controlling the turbine inflow exhaust gas flow rate, by using the adjustment unit, to reach a flow rate higher than zero and lower than the post-warm-up flow rate when an operating state of the internal combustion engine remains constant, such that a warmed state of the first exhaust gas control catalyst is maintained after the first exhaust gas control catalyst is warmed.