An immersion cooling device includes a refrigerant tank configured to accommodate a refrigerant liquid in which an electronic device is immersed; a seal tank configured to accommodate a sealing material and communicate with the refrigerant tank through an upper space of the seal tank, a cable connected to the electronic device being disposed in the upper portion space; and a partition member that, in a state in which a portion of the cable disposed in the upper portion space is immersed in the sealing material in a liquid state, partitions the upper portion space into a first space that is in communication with the refrigerant tank, and a second space that is in communication with an outside of the seal tank.