The work described here relates to a method for measuring the boundary layer transition in a “low-speed” and “atmospheric” wind tunnel for metallic aircraft model. The objective of the research is to improve the test technique and to clarify the precise procedure for transition measurements, especially for an aircraft model in such a typical wind tunnel. The boundary layer growing on the left wing of the ONERA-Model was investigated at the JAXA 6.5m×5.5m Low-speed Wind Tunnel (LWT1), using two visualizing methods: temperature-sensitive liquid crystal film, and infrared camera. Comparison of the results showed that the IR camera could be more effective using after cooling of the model surface.