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 canton of Bern.
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.
More than half a dozen fatal base jumping or wingsuit diving accidents have been reported in Switzerland in the past year.