Exhaust gas purifying apparatus of internal combustion engine

A reducing-agent supplying apparatus (28) of the present invention for supplying a reducing-agent to an exhaust gas purifying catalyst (20), detects abnormality such as leakage of the reducing-agent and contributes to restraining of deterioration of exhaust gas emission and destruction of the exhaust gas purifying catalyst (20) caused by the abnormality and includes the exhaust gas purifying catalyst (20) provided at an exhaust passage of an internal combustion engine for purifying harmful gas components in exhaust gas under presence of the reducing-agent, a reducing-agent supplying mechanism for supplying the reducing-agent to the exhaust passage upstream from the exhaust gas purifying catalyst, pressure detecting sensor (32) for detecting pressure of the reducing-agent in the reducing-agent supplying mechanism and ECU (35) for determining abnormality of the reducing-agent supplying mechanism (30) on the basis of pressure detected by the pressure detecting sensor (32).