A voltage controlled oscillator and a phase locked loop circuit having the same reduce power consumption by using charges leaked into a ground voltage terminal for an output driving operation with characteristics of both output terminals having different phases in a unit delay cell. The voltage controlled oscillator includes a plurality of unit delay cells connected serially. Each unit delay cell comprises a differential amplification unit and an output driving unit. The differential amplification unit compares a plurality of input voltages having different phases and amplifies the comparison result. The output driving unit, which is connected to both output terminals of the differential amplification units, drives an output voltage of another output terminal with a potential of one of both output terminals.