An information output device comprising: an event detection unit configured to detect an event occurring inside or outside a vehicle; a member identification unit configured to identify persons that can perceive the event when the event is detected as first members; an event storage unit configured to store event data related to the event that was detected in association with the first members, wherein the event data includes audio and video from the inside and outside of the vehicle; and a data output unit configured to automatically output the event data stored when the event detection unit detects another event similar to the event stored in the event storage unit as event data, wherein the another event is determined to be similar to the event stored in the event storage unit as event data when a conversation occurring in the vehicle includes a topic of conversation stored in the event data related to the event stored, or when a view visible from the inside of the vehicle includes a part of a view stored in the event data related to the event stored, wherein the member identification unit is configured to identify persons that can view the event data to be output from the data output unit as second members; and the information output device further comprises an output control unit configured to determine whether the second members include a person other than the first members associated with the stored event data to be output, and to permit the data output unit to automatically output the event data upon determining that the second members do not include persons other than the first members, and to prohibit the data output unit from automatically outputting the event data upon determining that the second members include a person other than the first members. an event detection unit configured to detect an event occurring inside or outside a vehicle; a member identification unit configured to identify persons that can perceive the event when the event is detected as first members; an event storage unit configured to store event data related to the event that was detected in association with the first members, wherein the event data includes audio and video from the inside and outside of the vehicle; and a data output unit configured to automatically output the event data stored when the event detection unit detects another event similar to the event stored in the event storage unit as event data, wherein the another event is determined to be similar to the event stored in the event storage unit as event data when a conversation occurring in the vehicle includes a topic of conversation stored in the event data related to the event stored, or when a view visible from the inside of the vehicle includes a part of a view stored in the event data related to the event stored, wherein the member identification unit is configured to identify persons that can view the event data to be output from the data output unit as second members; and the information output device further comprises an output control unit configured to determine whether the second members include a person other than the first members associated with the stored event data to be output, and to permit the data output unit to automatically output the event data upon determining that the second members do not include persons other than the first members, and to prohibit the data output unit from automatically outputting the event data upon determining that the second members include a person other than the first members.