With increasing population of older adults in need of care, caregiver's burden is becoming a major concern. We investigated the relative contributions of BPSD of care recipients, caregiver's background and the care environment to caregiver's burden assessed by using Zarit burden interview (ZBI). Among BPSD, inability of finding the way home, inability of managing money and fecal incontinence were the most difficult symptoms to cope with. A path analysis, by which we constructed a network model to clarify the contributions of the factors examined to the caregiver's burden, indicated that the severity of dementia, the feeling of "would rather die than be in the same condition" and the physical pain of the caregivers showed great direct influences on the score of the ZBI. In conclusion, we clarified kinetic and dynamic interactions of factors affecting caregiver's burden by using a path analysis. The model indicates that the caregiver's burden can be affected not merely by the illness of the care recipients but by the caregiver's background and the care environment.