To provide a heat dissipation fin of a substrate capable of suppressing degradation of heat dissipation performance while suppressing deformation of the substrate due to thermal stress.

The heat dissipation fin of a substrate comprises a bonding part having a bonding surface being bonded to the substrate, and a body extending from the bonding part and dissipating heat of the substrate. The body extends in the direction away from the bonding part. The bonding part has a high heat transfer region H corresponding to the body and a low heat transfer region L deviating from the high heat transfer region H, and a through region is formed in the low heat transfer region L on the bonding surface of the bonding part.