To heighten a self-diagnostic function of an obstacle detection device for detecting an obstacle at a railroad crossing or the like by utilizing, for example, millimeter wave band electric waves hardly influenced by weather, and to thereby improve furthermore the reliability of the device.

This device comprises sensor parts 1a, 1b, 1c arranged in the opposite angle direction of a crossing road 4, for transmitting the electric wave to an area in charge on the crossing road 4 and receiving a reflected electric wave from an obstacle, respectively; reflecting plates 2a1, 2a2b1, 2c1, 2c2 arranged oppositely to the sensor parts 1a, 1b, 1c across the crossing road 4, for reflecting each transmitted electric wave from the sensor parts 1a, 1b, 1c; and a control logic part 3 for controlling operations of the sensor parts 1a, 1b, 1c, determining existence of the obstacle on the basis of signal processing information of the reflected electric waves, determining normality/abnormality of a plurality of monitoring items related to the operation states of the sensor parts 1a, 1b, 1c, and performing self-diagnosis of the sensor parts 1a, 1b, 1c.

COPYRIGHT: (C)2005,JPO&NCIPI