Our paper empirically examines how the decision to purchase private insurance and hospitalization are made based on household income, socio-demographic factors, and private health insurance factors in both Japan and the USA. Using these two data-sets, we found some similarities and dissimilarities between Japan and the United States. As income of households rises, households have a positive effect on purchasing health insurance as a normal good. Another similarity between the two countries is seen in the income effect on risk of hospitalization, which is negative for both Japanese and US cases. For dissimilarity, the insurance premium effect on risk of hospitalization is positive for the Japanese case, while negative for the US case. Since the Japanese insurance data had variables such as payments per day of hospitalization if household gets hospitalized, insurance payments upon death of an insured person, and annuity payments at maturity, we tested to see if these characteristics affect the risk of hospitalization for households; we do not eliminate a possibility of adverse selection. For the US pure health issuance characteristics, an increase in premium of health insurance policies cause individuals to substitute more health capital investment which causes lower risk of hospitalization.