The final aim of this paper is to quantify pain degree by only using Electroencephalogram (EEG) measured with simple device. Pain degree dominates the choice and assessment of a treatment in clinical care. It is conventionally quantified using pain rating scales, although they are not capable of attaining objective values. Therefore, a method which can quantify pain degree objectively has great importance. In this paper, the possibility of quantifying pain degree by only using EEG measured with simple device is proposed. The proposed method is in an easy manner considering its time consummation and procedures. Significant difference in EEG features between pain-free, painful, and psychologically painful state were confirmed as the results of the experiment, showing the possibility of attaining objective pain degree by using EEG measured with simple device.