Disclosed is a method of copper leaching without reducing the growth of iron-oxidizing bacterium and the iron-oxidizing capacity when leaching copper from a copper sulfide ore with the use of a sulfuric acid solution to which iron-oxidizing bacteria and silver have been added. Also disclosed is a method of leaching copper from a copper sulfide ore, including adding a naturally occurring nitrogen-containing organic component to a leaching solution upon copper leaching from a copper sulfide ore with the use of, as the leaching solution, a sulfuric acid solution to which iron-oxidizing bacteria and silver have been added is provided.