A mine detector is provided for detecting buried land mines safely and promptly. A sensor head (12) is connected to a detector body (1) through hinges (11-1 to 11-4) and arms (12-1 to 12-3). The sensor head (12) includes a transmitting and receiving means for emitting electromagnetic impulses to the ground within a range of detection of land mines. When the transmitting and receiving means receives electromagnetic waves reflected from a land mine, information on the three-dimensional structure of the land mine buried under the ground is generated on the basis of the time of arrival of the reflected wave, the level of the reflected wave and the x and y coordinates of the transmitting and receiving means, and the information is displayed on a display (1). The detector is also applicable to the inspection of steel rods and bars for concrete reinforcement.