An internal combustion engine with an exhaust gas control apparatus, the exhaust gas control apparatus being placed in an exhaust passage of the internal combustion engine and the exhaust gas control apparatus including a selective catalytic reduction catalyst, the internal combustion engine including: a supply device configured to supply an additive to the exhaust gas control apparatus, the additive being ammonia or a precursor of the ammonia; and an EGR device configured to allow some of exhaust gas to flow back from the exhaust passage to an intake passage, an EGR passage being further downstream than a position of the supply of the additive by the supply device, the internal combustion engine being characterized by: an abnormality diagnosis device comprising an electronic control unit configured to: i) acquire a NO x inflow amount as the amount of NO x flowing into the exhaust gas control apparatus, ii) diagnose an abnormality of the exhaust gas control apparatus by using the acquired NO x inflow amount as a parameter in a case where the exhaust gas is not allowed to flow back by the EGR device, and iii) prohibit an abnormality diagnosis regarding the exhaust gas control apparatus in a case where some of the exhaust gas is allowed to flow back by the EGR device and the amount of the additive flowing back along with the exhaust gas exceeds an upper limit value. a supply device configured to supply an additive to the exhaust gas control apparatus, the additive being ammonia or a precursor of the ammonia; and an EGR device configured to allow some of exhaust gas to flow back from the exhaust passage to an intake passage, an EGR passage being further downstream than a position of the supply of the additive by the supply device, the internal combustion engine being characterized by: an abnormality diagnosis device comprising an electronic control unit configured to: i) acquire a NO x inflow amount as the amount of NO x flowing into the exhaust gas control apparatus, ii) diagnose an abnormality of the exhaust gas control apparatus by using the acquired NO x inflow amount as a parameter in a case where the exhaust gas is not allowed to flow back by the EGR device, and iii) prohibit an abnormality diagnosis regarding the exhaust gas control apparatus in a case where some of the exhaust gas is allowed to flow back by the EGR device and the amount of the additive flowing back along with the exhaust gas exceeds an upper limit value. an abnormality diagnosis device comprising an electronic control unit configured to: i) acquire a NO x inflow amount as the amount of NO x flowing into the exhaust gas control apparatus, ii) diagnose an abnormality of the exhaust gas control apparatus by using the acquired NO x inflow amount as a parameter in a case where the exhaust gas is not allowed to flow back by the EGR device, and iii) prohibit an abnormality diagnosis regarding the exhaust gas control apparatus in a case where some of the exhaust gas is allowed to flow back by the EGR device and the amount of the additive flowing back along with the exhaust gas exceeds an upper limit value. i) acquire a NO x inflow amount as the amount of NO x flowing into the exhaust gas control apparatus, ii) diagnose an abnormality of the exhaust gas control apparatus by using the acquired NO x inflow amount as a parameter in a case where the exhaust gas is not allowed to flow back by the EGR device, and iii) prohibit an abnormality diagnosis regarding the exhaust gas control apparatus in a case where some of the exhaust gas is allowed to flow back by the EGR device and the amount of the additive flowing back along with the exhaust gas exceeds an upper limit value.