Base jumping, or wingsuit jumping, is an extreme sport that involves free-falling off a cliff, bridge or another type of platform before activating a parachute.
The man was accompanied by two other jumpers on the escapade in Gastern valley, in the central canton of Berne.
He was the last to jump into the abyss and "crashed onto a rocky ledge," local police said.
Base stands for buildings, antennas, spans and Earth - the launchpads for the jumps.
In August last year, a 45-year-old Norwegian BASE jumper died after crashing into a meadow in the northeastern Saint-Gall canton.