CPU frequency scaling apparatus and method, which can select an optimal frequency based on a preset power versus efficiency table for a CPU when selecting the operating frequency based on the average load of the overall system during a specific time interval. The CPU frequency scaling apparatus includes a table generation unit for generating, for all cores, a power versus efficiency table, based on available frequencies for respective cores and power consumption values depending on loads at each frequency, an average load measurement unit for calculating an average load on all the cores, and a frequency determination unit for searching the power versus efficiency table for an optimal frequency, based on load information calculated by the average load measurement unit and current power consumption of all the cores, and determining a found optimal frequency to be a new operating frequency.