The present invention provides a diagnosis device with a display unit for diagnosing trouble of a vehicle by communicating with an electronic control unit of the vehicle. The diagnosis device comprises means for displaying, on the display unit, parameters relating to operation of the vehicle for selection of the parameters to be measured, means for displaying, on the display unit, the selected parameters to be measured such that triggering conditions for the parameters to be measured may be set, means for displaying, on the display unit, a group of signs of trouble with the vehicle such that a set of parameters to be measured corresponding to a sign selected from the group of signs may be set together with the triggering conditions for measuring the set of parameters to be measured, and means for displaying, on the display unit, result of measurement of the parameters to be measured.