Industrial management can be achieved in the improvement of productivities and goods qualities, only copy with international competition through technological renovation, This compels the renewal and augment of production equipments, for which more investment has to be projected. Equipment investment, However, has the possibility of assuring the expectation of profit, but the capricious reality of economical situation caused by inflation requires the precedent study of exmining, analyzing and assaying the effect of equipment investment for a long term. The resolution must depend on a technique of what is called engineering economy, which scrutinizes some samples of investment analysis under price fluctuations, which designates through a method of direct calculation that the only less scale of primal investment never bestows wider profit, and recognizes what contribution engineering economy has to the decision making of management.