A water supply device, and a steam supply device and a cooking device including the same are disclosed. The disclosed invention comprises: a housing installed in a body of a cooking device; a water tank having a storage space formed therein to store water, wherein the water tank is installed at the housing to be movable between an insertion position at which the inlet port is located in the receiving space and a withdrawal position in which the inlet port is exposed to the outside of the receiving space; and a connector which is installed at the housing so as to be movable in a longitudinal direction inside the receiving space, and moves in the longitudinal direction to move the water tank to the insertion position or the withdrawal position.