Police were notified of the situation last week and found hundreds of weapons and parts, including hand grenades, guns and ammunition, TheLocal.se reported.
"I've never seen anything like it in 26 years on the job," Bjorn Dahlback, chief police inspector, said.
Officers feared an explosion could happen and called in the bomb squad and the military to cordon off the house.
Police said they discovered that the man, identified as Bosse, had licenses for 557 of the weapons, but he is still suspected of violating a flammable and explosive weapon law.
Authorities decided to remove the weapons from the home, a job that will likely take two weeks.
"We still don't know how many weapons there are. He has licenses for 557, and we suspect he has at least that many, but we're not sure yet," Dahlback said.
Most of the weapons are from the 1960s and 1970s, but some are from the 1600s, TheLocal.es reported.
Bosse said he worked on collecting the items for 50 years and said the police were overreacting.
Dahlback said it is unlikely that Bosse will be reunited with his collection.