English is becoming a common language in our global society. Moreover, the verification of English ability is important. The Test of English for International Communication (TOEIC) is representative of a method to estimate English ability quantitatively. However, a significant amount of time is required to take TOEIC. For this reason, an easier measure of English ability is desirable. In this paper, we propose a method to predict English ability from changes in cerebral oxy- and deoxy-hemoglobin (Hb) concentrations by using 10-channel prefrontal cortex near-infrared spectroscopy data at a resting state. The data is obtained when the subjects are solving an English problem. Our proposed system could estimate 11 subjects' TOEIC scores with a 9.06% error rate.