Measurement of turbulent flow properties on natural convection in a model fire room was conducted using a Laser Doppler Velocimeter (LDV) and a fine thermocouple of 12 μ m diameter. The purpose of the experiment is to obtain data for validating the numerical simulation of a turbulent flow field where significant density variation caused by a large temperature variation is expected. This experiment quantitatively clarifies the turbulence characteristics of velocity and temperature which have hardly been measured by previous studies related to this problem. The results of this experiment provide valuable data for verifying 3-D numerical simulations with density variation. In this report, the experimental results on mean quantities are described.