A blinker judgment device for a vehicle includes: an information acquisition device that acquires surrounding situation information indicating a situation around the vehicle; and a control device that performs blinker judgment processing based on the surrounding situation information. The surrounding situation information includes image information of a target vehicle imaged by a camera. The control device performs: recognizing blinker flashing of the target vehicle based on the image information; checking, based on the surrounding situation information, whether or not there is a reasonable cause for the target vehicle to make a lane change, when the blinker flashing is recognized; and judging that the target vehicle is not in a process of the blinker flashing when the cause does not exist while judges that the target vehicle is in a process of the blinker flashing when the cause exists.