Zango struck in his sixth and final attempt and improved the ten-year-old world record, set by his coach Teddy Tamgho, by 15 centimeters.
Zango, World Cup bronze medalist, already holds the African record both indoors and outdoors.
No one has previously jumped over 18 meters indoors.
The British Jonathan Edwards flew 18.29 at the World Championships in Gothenburg in 1995. That record still stands as a world record outdoors.
In addition to Zango and Edwards, only five other three-step jumpers have climbed over 18 meters.