This study was conducted to determine the characteristics of chungkukjang with added isoflavone extracted from arrowroot and to determine its utility as a functional food substance. Crude isoflavone was prepared from arrowroot by the ethanol extraction method and frozen dried (AI). Samples of chungkukjang each had different amounts of isoflavone extracts added to them: 0 (control), 1.76 (AC1-chungkukjang), 3.52 (AC2-chungkukjang), and 7.11 (AC3-chungkukjang) g/kg. The pH, color, slime material content, calcium, and isoflavone of each sample were measured to investigate the quality and changes in isoflavone content. As AI increased, the pH of chungkukjang decreased to 7.46~7.53 compared to the pH of control (7.63). The slime material content range increased to 4.46~6.16%. However, there was no significant difference in the general components of chungkukjang between each of the groups (Con, AC1, AC2, AC3). In colors of chungkukjang, values for $L^*$, $a^*$, and $b^*$ decreased as AI increased. Meanwhile, the calcium content of AC1, AC2 and AC3 tended to increase by 11.18~12.82% compared to the control. This may be due to the influence of Ca in the arrowroot extract powder. There was a remarkable increase in total isoflavone content, by 30.81~130.66%, with an order of AC3>AC2>AC1. In all of the groups, the content of genistein and daidzein, aglycone form, increased dramatically, by 65.00~128.34%, and 89.38~142.91%, respectively, compared to the control. In AC3, in particular the genistin and daidzin content increased by 103.47% and 188.13%. These results showed that AI can be used as a source of isoflavone supplementation in chungkukjang.