This paper attempts to model the process of militarization of developing countries, based upon the so-called "fungibility" problems, i.e., a possibility of an official development assistance intended to promote productive activities to be actually transffered for non-productive activities. An econometric analysis using the panel data from African countries show that the level of fungibility, in particular that in military sector, depends on sectors targeted by official development assistance. For example, official development assistance for public health turns out to have low funbility.