The purpose of this study was to identify the impact of the behavioral, psychological, and functional symptoms of dementia on the burden of formal caregivers. A cross-sectional study was conducted among formal caregivers caring for residents with dementia in Japan. The Zarit Caregiver Burden Interview (ZBI) personal strain items, the Personal Self-Maintenance Scale (PSMS), and the Troublesome Behavior Scale (TBS) were used to assess the level of formal caregiver burden, activities of daily living (ADL), and behavioral and psychological symptoms of dementia (BPSD), respectively. The data from 445 respondents were analyzed using multiple linear regression analyses to predict the burden on formal caregivers. Disruptive behaviors, such as aggression, screaming, and a low ADL levels among residents with dementia were significantly correlated with higher formal caregiver burden. The results of this study support a positive relationship between BPSD, low ADL levels, and formal caregiver burden in caring for residents with dementia. These results illustrate the various characteristics of the burdens on staff members compared with those faced by individuals who provide informal care.