||We are analyzing the correlation between the sensing results for monitoring the office environment and the spectrum utilization of wireless system, such as WiFi and LTE. For improving the utilization efficiency of wireless communication, the demand and supply of frequency spectrum resources are predicted by this correlation. In order to conduct an experiment of correlation analysis, the sensing system which enables flexibly an addition or change of sensor devices is required. In this paper, the cloud sensing system by the wireless sensor network which enables flexible reconstruction is proposed. In cloud sensing, the data base server can accumulate the information acquired from the sensor terminal . In the constructed system, Arduino, WiFi, and MySQL are used as a host controller of sensor terminals, an infrastructure of wireless communication, and data base, respectively. Moreover, we show the experimental results given by the trial campaign of constructed system.