To provide a heat pipe suppressing deterioration of cooling performance even when a flat part is formed thin, or a heat receiving part is in a position higher than a radiating part.

In the heat pipe 1, a container 2 interior is provided in a state at less than the atmospheric pressure, and it is sealed with pure water. A groove type wick 6 comprising a plurality of ribs 4 and a plurality of grooves 5 is formed on an inner wall 2A of the container 2. A center line 22 of the rib 4 or a center line 23 of the groove 5 is slanted with respect to an imaginary line 21 vertical to the inner wall 2A of the container 2, and it is thinly machined to cool parts of electrical equipment.