Safe driving assistance device, operation management terminal, and safe driving assistance system

The purpose of the present invention is to provide a safe driving assistance technology which efficaciously reduces collisions regardless of environment or vehicle type. This safe driving assistance device 200 comprises: a connection destination detection unit 259 which detects and manages a connection state between the device and a connection destination device which is either a user interface 133 or an operation management terminal 112; a unique information setting unit 251 which, according to the connection destination device, sets unique information which identifies a type of a host vehicle; a position information acquisition unit 257 which acquires position information of the host vehicle; a host vehicle information management unit 252 which manages host vehicle information which includes the position information and unique information of the host vehicle; a vehicle-to-vehicle communication unit 255 which, by carrying out a communication with a safe driving assistance device which is mounted upon another vehicle, transmits the host vehicle information to the other vehicle and acquires other vehicle information; a risk assessment unit 254 which, using the host vehicle information and the other vehicle information, assesses whether a risk of collision exists between the host vehicle and the other vehicle; and output units 258, 256, 260 which output a result of the assessment.