A pH adjusting apparatus includes an electrolytic chip receiving a solution, an electrolytic chip loading station receiving the electrolytic chip, an input unit inputting electrolysis conditions, a control unit receiving the electrolysis conditions and controlling electrolysis performed in the electrolytic chip, and a display unit displaying the electrolysis conditions and a progress of the electrolysis. Thus, the pH of a solution can be adjusted easily and accurately, by precisely controlling a constant current, a constant voltage, and current and voltage application times, thereby enabling useful application in various biological assays such as cell lysis. Furthermore, the pH adjusting apparatus has small size and weight and can be operated for a long time after charging once due to low power consumption.