Investment is an important instrument of growth and competitiveness for non financial firms. However, these firms have limited financial resources (or liquidity) at their disposal. The financial constraint is defined as a conditionality to be met in order to have access to liquidity by assuming that the information held by shareholders is perfect, and that financial markets are efficient. We have attempted in this study to analyze empirically the impact of these financial constraint on the investments of Sub-Saharan manufacturing firms. We carried out an empirical analysis of a sample of 73 firms belonging to the different manufacturing sectors listed on the stock market during the period 1998-2009, and by taking inspiration from panel data methodology. The empirical tests emphasize the fact that the manufacturing firms of Sub-Saharan countries, including the smallest ones and those with which financial institutions have no close relations, witness an environment with a strong information asymmetry between borrowers and lenders. These firms are constrained in their access to external indebtedness due to the levelling-off of indebtedness. However, taking account of uncertainty could enrich the extension of this study.