A horizontal cooler module includes a heat sink formed of a stack of radiation fins, a base block tightly fitted into the bottom side of the heat sink, and heat pipes each having a first extension arm respectively tightly inserted through the radiation fins and a second extension arm respectively fitted into the bottom open grooves of the base block with a respective flat wall portion of the second extension arm exposed to the outside of the base block and kept in flush with the bottom wall of the base block for direct contact with an external electronic chip to transfer heat energy from the electronic chip to the heat sink for quick dissipation.