The Mint House (Mynthuset in Swedish) is the name of the old house which was integrated into the wall east of the North Gate. The house is 15-30 years older than the wall itself. Due to its location and the terrain, it was difficult to place the wall outside the Mint House. The house was also diagonally positioned in relation to the intended stretch of the wall so that extensive demolition would have been inevitable. Therefore, they chose instead to build the house into the wall, reinforce it and let it become a tower in the wall. Sometime in the early 18th century most parts of the house were demolished, so only some traces of it are now visible.

It is likely that coins have been minted in the house for some time, hence the name. Gotland coins were minted on the island from about 1150 until 1565.