This paper shows that experimental results for three-dimensional odor plume tracking using a multicopter with semiconductor-type gas sensor array. The 3D gas tracking aerial robot for monitoring of forest fire is developed, and the quadcopter has four gas sensor pairs put on under each rotor to expose the sensors to localized airflow made by rotors, which the sensor pairs will be prepared to detect a change of odorants and generation of hydrogen in early stage of fire. Here it is investigated that detecting odorants and estimating of a direction of arrival (DOA) of the source. The results of preliminary experiments of the 3D ethanol gas plume tracking by the aerial robot are illustrated. Then aspirating odor around the rotors of the multicopter, the gas sensor array can be responded to the gas concentration gradient even though the sensors are not separated with any airflow rectifiers. The results show that the gas sensor array in the rotors can express the DOA of gas source.