Cooling device

A cooling device comprising:

• an evaporator in which a refrigerant is vaporized by heat generated by a heating element;
• a condenser which is located above the evaporator and in which the vaporized refrigerant is condensed by exchanging heat with an external fluid;
• a first connection pipe which comprises a first end portion communicating with the evaporator and a second end portion communicating with the condenser, and which guides the refrigerant vaporized in the evaporator to the condenser;
• a second connection pipe which comprises a first end portion communicating with the condenser and a second end portion communicating with the evaporator, and which guides the refrigerant condensed in the condenser to the evaporator;
• and
• a third connection pipe connecting a portion of the first connection pipe positioned between the first end portion and the second end portion of the first connection pipe and a portion of the second connection pipe positioned between the first end portion and the second end portion of the second connection pipe, and a connection position between the third connection pipe and the first connection pipe being higher than a maximum liquid level height of the refrigerant in the second connection pipe when the cooling device is in operation.