An object of the present invention is to provide an in-vehicle traffic information notification device which, even when it is difficult to specify a traveling route of an own car, can notify adequate traffic information to users. A passage probability calculator of the traffic information notification device calculates a passage probability which is a probability that the own car passes an occurrence position of each traffic hazard obtained by a traffic information receiver, based on a current position of the own car detected by a current position detector and traveling history data stored in a traveling history data storage. A display unit and a sound output unit notify occurrence information of the traffic hazard to the user by a mode corresponding to the passage probability of the traffic hazard.