A way to clarify the measurement of social capital is the differentiation of its bases on opportunity and exchange. Social capital based on opportunity incorporates organizational participation, network strength, trust, helping and continuing relationships, whereas social capital based on exchange consists of the investment and reciprocation of help. An empirical hint for verifying the social capital measurement is its predictability of morale. Based on survey data from 201 Japanese residents, the study examined various measurements of social capital based on 10 indicators and their prediction of morale. Results revealed that social capital based on exchange was sufficient to contribute to morale, and essentially represented the salutary part of social capital. As social capital based on opportunity had no contribution to morale, a refined measurement of social capital can just concentrate on its basis on exchange.