In an in-vehicle information processor 100 including a communication device 104 which acquires traffic signal information regarding the lighting state of a traffic signal 401 and a display 106 which executes signal waiting time notification based on the traffic signal information acquired by the communication device 104, the display 106 starts the signal waiting time notification when the speed of a own vehicle 300 becomes equal to or smaller than a predetermined threshold value. For this reason, even in the case where the own vehicle 300 has stopped before the traffic signal for a certain reason although it tried to pass the traffic signal, the signal waiting time notification is performed again when the speed of the own vehicle 300 becomes equal to or smaller than the predetermined threshold value. Therefore, it becomes possible to perform the signal waiting time notification more accurately when necessary.