Abstract: The present invention provides a method for producing an internal olefin for obtaining an internal olefin sulfonate having high low-temperature stability, a method for producing an internal olefin sulfonate using the internal olefin, and a low-temperature stabilization method. The method for producing an internal olefin of the present invention includes the step of internally isomerizing an ?-olefin having 8 or more and 24 or less carbon atoms using a fixed bed reactor in which solid acid catalyst particles are packed in a reaction tube. A ratio (D/dp) of an inner diameter D of the reaction tube to an average particle diameter dp of the solid acid catalyst particles is 25 or more.