Vehicle driving mode display device and program for displaying vehicle driving mode

A vehicle driving mode display device judges whether or not a following first condition or a following second condition is satisfied in a case that a vehicle is driven within a tolerance range, and if satisfied, issues a warning. The first condition: in a case that a difference between a standard speed indicated by the running speed pattern and the vehicle speed is gradually widened as time elapses. The second condition: in a case that the vehicle speed exceeds the tolerance range within a predetermined allowable time period when an acceleration at the moment is presumed to be kept.