This paper investigates comparative policy effects of public credit guarantee and credit insurance for small medium enterprises (SMEs). The public credit guarantee program is to support funding of SMEs with pay-back guarantee by government sponsored public credit guarantee organization, while the public credit insurance program is to insure SMEs' claims on their sales by also public sponsored organization. The former helps SMEs at the funding stage, while the latter at the products sale stage. According to our theoretical comparative studies, policy channel of the former is restricted in the early stage of funding, whereas the channel of the latter is more extensive covering the last stage of sales as well as the early funding stage. The insurance program recursively extends its policy channel from the last stage to the first stage of funding thru creating market for funding based on the certificate of insurance on the SME's claim on their sales. In essence, the insurance program improves cash flows of the SMEs removing uncertainty of the sales claims default that generates the more extensive policy effects. Empirical results prove our theoretical conjecture that credit insurance is more efficient (by restricting moral hazard) and effective (by creating more extensive policy channel) than guarantee program in the supports of SMEs.