With an aim to improve quality of life in caregivers of dementia patients, we examined the effect of regular exercise on caregivers' sense of burden and their physical symptoms. Participants were 31 elderly caregivers living with older patients diagnosed with Alzheimer's-type dementia. They were randomly assigned to either the intervention group, who were prescribed regular exercise with moderate-intensity: 3 metabolic equivalents (3METs), 3 times per week for 12 weeks, or the control group, who did not receive any prescription. In the intervention group, significant reductions in the Zarit caregiver burden interview (ZBI) score and in the frequency of feeling fatigued, and an improvement in quality of sleep were observed at follow-up (p < 0.05), while no such changes were observed in the control group. These results suggest that obtaining sustainable habit of moderate exercise may improve quality of life in caregivers of demented patients.