Lubricating oils have been used on various machines and are essential for the normal operation of the machines, but they degrade with operation time, and thus various lubricating oil analyses are performed in the field. We have already proposed a degradation diagnostic method using the color of the membrane patch. Thus this method makes it possible to evaluate insoluble oxide productions and solid particles in lubricating oils in the early stages of degradation, whereas this method still leave room for improvement in terms of cost and convenience. Therefore, we proposed Lubricating oil Image Analysis (LIA), which uses the color information of the lubricating oil itself. This method is capable of quantitative color analysis from RGB values of lubricating oil images taken with a digital camera, and makes it possible to use as a degradation diagnostic method easily and at a low cost. In this paper, we describe the process of developing a Lubricating oil photographing equipment (Lope), which we designed and manufactured. Additionally, we investigated its usefulness and considered the mechanism of color development associated with degradation. Consequently, LIA makes it possible to diagnose the degree of degradation.