An abnormality determination device and an abnormality determination method of a vehicle that includes a stepped type automatic transmission capable of forming a plurality of speed change steps are provided. The presence/absence of an abnormality of an element related to formation of a predetermined speed change step is determined in a state of the vehicle where the predetermined speed change step is formed. Information about the abnormality determined to be present is then stored. If the information about the abnormality is stored when the vehicle is to newly start to run, the predetermined speed change step where the abnormality stored occurred is established, and the presence/absence of the abnormality of the element related to the formation of the predetermined speed change step is re-determined.