This paper presents an examination of effects of a child allowance on fertility under a pay-as-you-go pension system. In these analyses, the child allowance is financed by taxation of two kinds: an income tax and a consumption tax. Comparative static analyses show that a child allowance financed by income tax revenues can always raise fertility. Similarly with income tax, a child allowance financed by consumption tax can always raise fertility. Furthermore, our paper presents examination of optimal child allowance and transfer for older people. (author abstract)