A cooking device includes a lower heating plate unit, an upper housing member, and at least one positioning mechanism that includes a lower coupling unit fixed to the lower heating plate unit, an upper coupling member fixed to the upper housing member, an actuating member disposed on the upper coupling member, and a pin connected to the upper coupling member. The cooking device further includes an upper heating plate coupled to the upper housing member. Removal of the upper heating plate results in the actuating member being pushed resiliently to have a positioning portion thereof engaging a guiding hole of the lower coupling unit, so that the upper housing member is limited to move to be parallel to and spaced apart from the lower heating plate unit.