The present disclosure is to provide a heat sink capable of improving cooling efficiency of a heat radiation fin and exhibiting excellent cooling performance with respect to a cooling target regardless of an installation posture of the heat sink, and capable of being installed even in a narrow space.The heat sink includes: a heat transport member having a heat receiving portion thermally connected to a heat-generating element and including a first wick structure; a tube body connected to a heat insulating portion or a heat radiating portion of the heat transport member and including a second wick structure; and a heat radiation fin group which is thermally connected to the tube body and in which a plurality of heat radiation fins are arranged, in which, the heat transport member has an integral internal space that communicates from the heat receiving portion to a connection portion with the tube body and is sealed with a working fluid, the internal space of the heat transport member communicating with an internal space of the tube body, and the first wick structure includes a branch portion branched in a thickness direction of the heat transport member and multi-stage stem parts extending from the branch portion in a predetermined direction.