To investigate the characteristics of the caregiving experience according to age at onset of dementia to adapt support programs. Fifty-seven spouse caregivers of persons with early-onset dementia (PEOD) and 93 spouse caregivers of persons with late-onset dementia (PLOD) participated. The characteristics of the caregiving experience were assessed using questionnaires. We compared the two groups according to age at onset of the disease using a multivariate test, Pillai's Trace test. The analysis showed that there were similarities and differences between the two groups of spouse caregivers. All spouse caregivers were confident in their caregiving role and fairly well prepared for future needs and reported mild depressive and anxious symptoms. However, they lacked informal support, had low confidence in requesting respite care and reported effects on their health. Compared to spouse caregivers of PLOD, spouse caregivers of PEOD had more severe perceptions of the cognitive disorders of persons with dementia (PWD) and had a better sense of preparedness and knowledge of services. Spouse caregivers of PLOD were more confident in their ability to control disturbing thoughts. The results suggest that programs should provide information on support networks to improve preparedness for spouse caregivers of PLOD as well as emphasizing positive coping strategies for caregivers of PEOD to maintain good-quality relationships with PWD, which influences the perception of the symptoms. For both groups, family relationships should be considered.