In order to establish the fire safety design of ship engine room, it is important to understand the characteristics of oil pool combustion, the properties of smoke, the conditions of fire spread and smoke movement with heat diffusion. In our previous study, the oil burning experiment was executed to investigate the distinctive features of pool combustion and smoke. And the experimental and numerical analyses of smoke movement were carried out using the 1.2m sized cubic box as a substitute for simplified engine room model. In this study, the experiment of smoke movement and diffusion in the 1/15 scale model of engine room with smoke-producing agent was carried out for the fire safety design on fire detection, fire fighting and evacuation. Moreover, a three-dimensional numerical analysis using k-ε based CFD model was performed to investigate the situation of smoke diffusion in an engine room. Furthermore, the numerical analyses of smoke and heat diffusion in the full-scale engine room model were executed using the result of oil burning experiment and the numerical method that is already proved the validity to grasp the state of smoke movement. From the interpretation of these results, the phenomena of smoke diffusion in an engine room under several fire conditions can be clarified. By the experiment and the calculation on smoke movement in an engine room, a lot of useful information is obtained for the design of evacuation systems and the arrangements of smoke sensors.