The case in question concerns a man in Malmö, convicted and fined 1,200 kronor ($184) by the district court in the city for the illegal possession of a dangerous object.
In his defence the man argued that he was using the baseball bat to hit balls for his dog to chase.
Furthermore he argued in his testimony that as he had previous been assaulted on two occasions he felt safer in the knowledge that he had a baseball bat with him in the passenger seat of his car.
According to Swedish law the possession of dangerous items such as knives, and other weapons "designed to be used as a weapon in crimes against life or limb", are not permitted in a public place.
The defendant in the case has argued that a baseball bat is not covered by the law and pointed out that it has a number of other uses.
The appeals court however based its rejection of his appeal on the grounds that he kept it on apparent display in his car, and thus can be construed to conform to the legal definition of a dangerous item.
The Supreme Court on Monday gave the man leave to appeal with a date for the hearing to be announced later.