A lamp base having a heat sink is connected to a bulb having two electrodes. The lamp base includes a heat sink, a first electrically conductive piece, a second electrically conductive piece, and leads. The heat sink comprises a heat-dissipating base formed with a trough for accommodating the bulb therein. The first electrically conductive piece is fixed in the trough and is electrically connected to an electrode of the bulb. The second electrically conductive piece is fixed in the trough and is electrically connected to the other electrode of the bulb. The second electrically conductive piece is electrically insulated from the first electrically conductive piece. The leads are electrically connected to the first electrically conductive piece and the second electrically conductive piece respectively. With the heat sink dissipating the heat generated by the bulb, the lamp base has extended lifetime.