An analyzer of the invention adequately analyzes a change in road network by using probe information generated with driving of a vehicle. This analyzer determines a traffic amount of vehicles passing through a specified section included in the road network from a plurality of the probe information accumulated over a predetermined period. The analyzer also determines a discontinuity rate, which is a rate of incidents that vehicle locations are discontinuous in the specified section, from the plurality of probe information accumulated over the predetermined period. The analyzer detects a change in the road network, based on a degree of change between traffic amounts in two different periods with respect to the specified section included in the road network and a degree of change between discontinuity rates in the two different periods. The detected change in the road network can be used for survey of the road network. [Drawing selected] Fig. 1