The objectives of the present study are to examine risk factors for the heavy burden of caring for demented patients as well as factors that may affect on the level of utilization by carers of public services under current long-term care insurance in Japan. A cross-sectional study was conducted in the outpatient clinic for dementia, Department of Geriatric and Complementary Medicine, Tohoku University Hospital, Japan. Behavioral and psychological symptoms of dementia were significantly associated with heavy caregiver's burden as measured by Zarit's caregiver burden interview ( P = 0.002 r = 0.45). A heavy caregiver's burden led to depressive symptoms ( P = 0.01 r = 0.30), especially in spouse caregivers. Despite the presence of depressive symptoms, spouse caregivers less frequently used public services than non-spouse caregivers ( P < 0.001). On the other hand, the level of service provision was decided primarily by the severity of dementia and physical disability of patients, but not the caregiver's burden. Early detection and management of dementia-associated behavioral and psychiatric symptoms could be important to reduce caregivers’ burdens and to prevent them from developing depression. Spouse caregivers should be encouraged not to hesitate to use public services.