This paper is focused on the sustainability of public rental housing policy. We have analyzed the general fiscal conditions of central government, the public welfare fiscal conditions, the public expenditure on rental housing, and the Korea Land & Housing Corporation (LH) financial structure. Central government fiscal conditions is controlled by the midium-term fiscal operation plan(2010~2014) and fiscal rules. And the fiscal mandatory expenditures on welfare is increased rapidly by the expansion of beneficiaries, but the fiscal discretionary expenditures particularly on public rental housing can be gradually cut down. LH, the dominant agency responsible for affordable housing, is now confronted with financial distress accruing to excessive burden for public rental housing construction. As a result this paper, we find the discrepancy between the fiscal conditons and public rental housing policies. We suggest the fiscally sustainable rental housing policy. Firstly, the construction plan should be realized reflecting the market and fiscal conditions. Secondly, the provsion and financing system of rental housing should be rebuild within the government fiscal condtions and financial ability of LH.