Driving assistance device

A driving assistance device that

• acquires detection results by a plurality of detection sensors installed at different places with respect to a vehicle, each of the detection sensors transmitting a probe wave to surroundings of the vehicle, the detection sensors being in a positional relationship in which a reception wave including a reflected wave obtained by the probe wave being reflected by an object around the vehicle is allowed to be mutually received,
• performs a probe wave detection process of identifying a position of the object by triangulation using a first detection distance calculated by a detection sensor serving as a transmission source receiving a reflected wave of the probe wave as a direct wave and a second detection distance calculated by another detection sensor different from the transmission source receiving a reflected wave of the probe wave as an indirect wave, based on the acquired detection results by the detection sensors,
• performs an image detection process of identifying a position of an object around the vehicle as a result of an image recognition process on a captured image captured by an imaging device included in the vehicle, and
• in a case where there is a proximate object that is an object whose position is identified in the image detection process, and whose first detection distance is allowed to be calculated but whose second detection distance is not allowed to be calculated in the probe wave detection process, and a difference between a distance from a position of the proximate object identified in the image detection process to the detection sensor and the first detection distance to the proximate object is less than a threshold value, sets the proximate object as an assistance target for which driving assistance of the vehicle is performed.