Private schools are nonprofit organizations because they provide public and knowledgeable learning services. Whether private schools can have regular development and smooth functions depends on the governance mechanisms of the school boards. Financial deterioration is a very important index especially for those poor management schools. At present, the financial reports of private schools are audited by certified public accountants (CPAs) and disclosed openly to be supervised by outsiders. This paper examines the effect of the governance mechanisms in private senior high schools on the selection of CPAs and disclosure level of financial information. The research samples include 209 private senior high schools in the academic years 100 and 101. Three research findings are presented in this paper. 1. Private senior high schools that are more willing to disclose information such as their board size and religious sect support are also more willing to disclose the financial reports. 2. Private schools that disclose the financial reports and have the four characteristics— higher educational costs, more spending on teaching and research, board size disclosure, and longer establishing years— prefer to select the CPAs that have good audit quality. However, private schools with religious sect support and government subsidies to School Actualization Plan are less willing to choose the CPAs with good audit quality. This indicates that private schools with better governance mechanisms put more emphasis on financial information quality. 3. Private schools that disclose their board sizes, receive government subsidies to School Actualization Plan, and are affiliated with Ministry of Education in Taichung Office have a higher level of financial information disclosure. Private schools with a religious background and religious sect support, however, have a lower level of financial disclosure. The research findings conclude that governance mechanisms of private senior high schools affect their CPA selection and level of financial information disclosure. The findings have implications for the making of related polices in the future.