To suppress the deterioration of display, even if data regarding driving distance cannot be obtained in a navigation device called as a 'hybrid type'.

In a sensor 310 for outputting a pulse signal according to vehicle drive distance, a measuring instrument 100 for vehicles for displaying vehicle information including the drive distance based on the pulse signal, and a navigation unit 200 for inputting distance data or pulse signals regarding the drive distance obtained by processing the pulse signals outputted from the measuring instrument 100 for vehicles at a fixed reading cycle for calculating the current position of the vehicle, and at the same time, displaying road traffic information including display obtained by compositing the current position on a map by the measuring instrument 100 for vehicles, based on map data being read from a map information record medium 230, the estimation value of a value to be inputted this time is obtained from the amount of change between the previously inputted value and the value before this, to calculate the current position when the distance data or the pulse signals could not be inputted.