A water dispenser with alkaline water production function, which is suitable for use in a refrigeration device having at least one refrigeration compartment and at least one door for allowing access into the refrigeration compartment, such that the water dispenser is positioned at an inner side of the door facing the refrigeration compartment, characterized by comprising: at least a first reservoir suitable for filling with water; at least a second reservoir suitable for filling with water and located in a bottom part of the first reservoir, wherein the second reservoir can be attached and removed by the user to said door; at least one electrolysis unit which is located between the first reservoir and the second reservoir and has: o at least one membrane blocking water passage to prevent water in the first reservoir and the second reservoir from mixing with each other while allowing H + ion to pass between the first reservoir and the second reservoir, o at least one cathode positioned at a side of the membrane facing the first reservoir so as to contact the water inside the first reservoir, and o at least one anode positioned at a side of the membrane facing the second reservoir so as to contact the water inside the second reservoir; at least one power source which is in connection with the anode and cathode and applies voltage to the anode and cathode at the same or different, constant or varying values to generate an electrolysis reaction in the water inside the first reservoir and the second reservoir to produce alkaline water in the first reservoir, wherein H + ions formed at the anode can move through the membrane towards the cathode; at least one discharge unit for discharging the alkaline water formed inside the first reservoir; at least one input unit which allows the user to select a hardness value, wherein the hardness value is defined as one of the desired pH value of the water, the ORP value, the amount of H + ion value and dissolved H 2 values, and to activate an alkaline water production process; at least a first sensor which is located in the first reservoir and allows measuring an amount of H + ions, the pH, the ORP value or dissolved H 2 values in the water inside the first reservoir; and at least one control unit which is in connection with the input unit and the first sensor and controls the power source based on the data received from the input unit and the first sensor so that the amount of H + ions, the pH, the ORP value or dissolved H 2 values inside the first reservoir is adjusted. o at least one membrane blocking water passage to prevent water in the first reservoir and the second reservoir from mixing with each other while allowing H + ion to pass between the first reservoir and the second reservoir, o at least one cathode positioned at a side of the membrane facing the first reservoir so as to contact the water inside the first reservoir, and o at least one anode positioned at a side of the membrane facing the second reservoir so as to contact the water inside the second reservoir; H + ions formed at the anode can move through the membrane towards the cathode; at least one discharge unit for discharging the alkaline water formed inside the first reservoir; at least one input unit which allows the user to select a hardness value, wherein the hardness value is defined as one of the desired pH value of the water, the ORP value, the amount of H + ion value and dissolved H 2 values, and to activate an alkaline water production process; at least a first sensor which is located in the first reservoir and allows measuring an amount of H + ions, the pH, the ORP value or dissolved H 2 values in the water inside the first reservoir; and at least one control unit which is in connection with the input unit and the first sensor and controls the power source based on the data received from the input unit and the first sensor so that the amount of H + ions, the pH, the ORP value or dissolved H 2 values inside the first reservoir is adjusted.