A drinking water supply device may include a filtered water pipe, a flow rate sensor, a water supply pipe, a mineral supply pipe provided with a mineral supply valve, a mineral cartridge configured to connect to the mineral supply pipe, a mineral mixer configured to connect to the water supply pipe and the mineral supply pipe and configured to allow mixing of the minerals from the mineral supply pipe with the filtered water in the water supply pipe, a pump, a discharge pipe configured to connect to the mineral mixer and the water supply pipe, and a controller configured to control an output voltage of the pump in order to adjust an amount of minerals that are supplied to the water supply pipe based on a flow rate sensed by the flow rate sensor.