We have developed an electromagnetic prospecting system using a drone for searching for automobiles buried by a landslide. The system consists of an drone, an 1.6 m long electromagnetic (EM) sensor with a GPS receiver, an ultrasonic distance sensor for monitoring the height of EM sensor from the ground surface and a WiFi serial transceiver for controlling the EM sensor and monitoring the measured data. The drone suspends the EM sensor and EM data are acquired during the flight. The distance of drone-sensor separation is crucial to avoid EM noise caused from the drone motors and to stabilize the flight of drone On the basis of field experiments, we adopted a separation of 4 m and attached a vertical tail to the aft end of EM sensor witch can stabilize the flight at a speed of at least 2 m/s. The height of EM sensor should be monitored because it affects the EM data significantly. We have tested the system at an experiment site where there are two cars embedded at depths of 1.5 m and 3 m respectively. The close-area search clearly indicated the location of the shallow car, and there was a slight indication of the deep car.