A method of manufacturing a heat dissipating device includes steps of providing a heat dissipating fin and a heat pipe. The heat dissipating fin includes a fin body, a through hole and a collar portion, with the through hole formed on the fin body, with the collar portion extending from a periphery of the through hole and having a first U-shaped protruding ear, with the first U-shaped protruding ear having a first opening, with the heat pipe having a heat dissipating end and a heat absorbing end, and with the heat dissipating end opposite to the heat absorbing end; inserting the heat dissipating end into the through hole and the collar portion; and punching the collar portion to shrink the first opening of the first U-shaped protruding ear, such that the collar portion fixes the heat dissipating end in a tight-fitting manner.