This disclosure relates to a heat pipe includes a tubular body and a capillary structure. The tubular body has an inner surface. The inner surface forms a sealed chamber. The capillary structure is located in the sealed chamber and arranged on the inner surface. The tubular body includes a condensation section and an evaporation section connected to each other. The capillary structure includes a cold section and a heat section connected to each other. The cold section is disposed on the condensation section, and the heat section is disposed on the evaporation section. A wall thickness of the cold section is greater than a wall thickness of the heat section.