The Rooster Tower is named after the wind vane on the roof of the tower. The tower was built in the 15th century as a residential, defensive and gate tower.

The castle was originally entered from the second floor through an opening in the wall via a ladder. The ladder could be pulled inside the walls to prevent a potential attacker from using it.

The entrance was rebuilt in the 15th century with the construction of the Tower of Flowers, from which the entrance to the castle was via a drawbridge. In the centre of the outer wall of the tower you can see a doorway covered with bricks, which in the Middle Ages was the site of the drawbridge. The stairs descending from the rooster tower are the oldest preserved stairs in Häme Castle. The stairs were built at the beginning of the 15th century. They are partly in ruins. The stairs lead to a small doorway at the bottom of the rooster tower, which gave access to the castle when the drawbridge was up.

The remains of the gatekeeper's chamber can be seen to the right of the old doorway. The large pits in the floor are probably counterweights or trap holes for the drawbridge.