Locals spotted the man, who is understood to live in the area, sneaking into the Lidl store before it went up in flames at around 8.40pm.
He is reported to have chased away witnesses with an iron pipe before going back inside the building, which started burning soon afterwards.
Tobias Sundström, an operator for the region's police force, told Swedish tabloid Aftonbladet that emergency services initially tried to coax him out but he refused help. Firefighters were prevented from going inside the building to tackle the blaze in case they were attacked.
"In the end he broke out through a wall," said Sundström.
"It's the craziest thing we have seen," he added in a separate interview with Sweden's TT news agency.
Sundström confirmed that the suspect was arrested at the scene. Fire crews from three cities then spent several hours controlling the fire.
The suspect has not been identified but is understood to have been born in 1991.
"He was pretty upset so we'll let him calm down a bit. We're talking to witnesses at the scene," Magnus Holmström a duty police officer told Aftonbladet.
The store was closed at the time of the alleged arson attack, however a spokesperson for Lidl told The Local on Tuesday that staff were being offered counselling.
"We have started our emergency support group today so they are being taken care of," said Martin Jarstål, press manager for the supermarket chain in Sweden.
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"They are getting professional help from psychologists and will get the chance to talk about what happened."
Jarstål said that the company had not yet been given the chance to inspect the damage.
"We are not open today and we don't know as of yet when we will have access," he said.
Police forensic teams are expected to continue their investigations at the scene throughout Tuesday.