It is built on steep rocks near to the center area of the city. Founded as a defensive fortress, the Castle was used for protection and arrest of important people throughout history. It was restored by Seljuks, first, and later by the Ottomans. There are mosque, quartermaster depots and the fort commander's house. It is known that there is a stair with 362 steps, called as Ceylan, coming from the castle and reached to the city. It is believed that it was found in AD. 5. or 6. Century. There is a beautiful scene of Tokat from the Castle. Particularly the view of the region with full of historical monuments at around Sulusokak makes the viewers to have a nostalgic feeling. There is Ayar Castle in the highest tower of the Castle.