The purpose of the present study was to examine whether chronic aerobic exercise affect the cognitive function of older adults. A total of 24 subjects who varied in self-reported physical activity history participated in this study. According to the condition of the physical activity level (low: 3,200kcal per week), subjects were divided into 2 groups. The frontal lobe cognitive function was measured by the Digit Span Forward test, the Trail Making test, the Immediate recall words test, the Delayed recall words, the Controlled Oral word association test, and the finger tapping test. The Cognitive function was assessed by neuroelectrical response, an event-related potential (ERP) at Fz, Cz, and Pz during oddball task. As the results, Frontal lobe cognitive function data revealed that aerobic exercise groups exhibited improvement compared to the control groups. The aerobic exercise group exhibited larger P300 amplitude than the control group. The aerobic exercise group exhibited shorter P300 latency than the control group. The results of the analysis revealed that long-term aerobic exercise may be beneficial to aspects of cognition, particularly among older adults. It was concluded that long-term aerobic exercise is associated with attenuation of cognitive decline in older adults.