This study is an experimental study on behavior of the fire plume ejected from an opening under soffit with H-beam beneath the tip. We used a large-scale experimental apparatus. Also, experimental conditions are the opening size, soffit size, handrail, and fire source. The temperature prediction under the soffit is proposed by using the Watanabe model (predictions of ceiling jet temperature by combining a two-layer zone model) and the Ohmiya model (predictions of the vicinity of vertical wall temperature) in combination. It was confirmed that the calculated value and the experimental result mostly match.