A heat pipe structure including a pipe body and a working substance is provided. The pipe body has two closed ends opposite to each other, an inner surface, a compressed portion, and an expanded portion. The inner surface and the two closed ends form a cavity. The compressed portion includes a plurality of first grooves formed at the inner surface. Any one of the first grooves includes a first width. The expanded portion includes a plurality of second grooves formed at the inner surface. Any one of the second grooves includes a second width, and the first width is approximately equal to the second width. The working substance is contained in the cavity.