The automobile rear structure includes a diffuser which is arranged on a vehicle-body rear side of a muffler and is configured to interfere with exhaust gas discharged from the muffler so as to make a portion of the exhaust gas flow downwardly, and a flow rectification plate which is arranged below the muffler and guides the downwardly flowing exhaust gas in the direction along an air flow flowing below the floor of the vehicle body to merge the exhaust gas into the air flow. The exhaust gas discharged downwardly from a space defined between a front end portion of the diffuser and a body portion of the muffler is guided in the direction inclined downwardly toward the rear side of the vehicle body and, thereafter, is guided in the direction along the air flow flowing below the floor of the vehicle body, and is merged into the air flow.