A diagnostic information collection apparatus includes: multiple abnormality detection sections corresponding to respective diagnostic objects in a vehicle to detect an abnormality; and a memory. Each abnormality detection section includes: an abnormality occurrence determination unit; an abnormality confirming unit; a normality conforming unit; a state information generation unit that generates state information indicative of a determination result whether abnormality decision is in progress; and an abnormality-related information processing unit that controls the memory to store identification information about the diagnostic object when the abnormality occurrence determination unit determine the abnormality occurrence at a first time, specifies another abnormality detection section having state information indicative of abnormality decision in progress, and controls the memory to store identification information of the specified another abnormality detection section.