A blood flow image diagnosis device which diagnoses a blood flow map by separating, on the basis of a plurality of blood flow maps covering a specified time including one or more cardiac beats, a blood flow of a surface layer blood vessel observed in a surface layer in an observation region of a body tissue from a background blood flow of a peripheral background region. The device distinguishably displays a first blood flow map of the surface layer blood vessel and a second blood flow map of the background blood flow. The device calculates and compares information on a blood flow including blood flow value, blood flow waveform, or blood vessel diameter in the first and second blood flow maps, and displays the calculated information.
