A experimental study on an extended flame and its behavior issued from an opening was conducted using a model compartment. A rectangular diffusion burner was adopted as a model fire source, and was set at the end wall in the compartment. The three different flow rate of propane gas of 30, 40 and 60 1/min were employed. We changed the opening area as full opening and 1/3 opening. The effects of pent-roof and fascia on the length of extended flame were also tested. The temperatures along the vertical wall during a fully developed fire were visualized using an infrared image processor and were also measured by means of thermocouples. The temperature contour maps were made based on both temperature data, and their crose correlation was elucidated.