A 48-year-old man described as “rampaging” by cantonal police waved a bottle of gas from a first-floor balcony after firing up a chainsaw and damaging the interior of his home in Seftigen on Saturday afternoon.
Officers evacuated neighbours from four homes for safety reasons before the man set fire to his apartment, police said on Sunday.
He was eventually arrested and no-one was injured in the incident, police said.
The suspect, apparently suffering from mental problems, was taken to a special institute for observation.
Police said they found canisters of gas, jerry cans of petrol and a chainsaw in the badly damaged apartment.
A total of 37 fire fighters ensured the fire did not spread, and damage to the apartment building was limited.
Evacuated neighbours returned to their homes by Saturday evening.
The regional prosecutor has launched an investigation into the matter.