A blood flow analysis device includes a blood vessel region extraction unit that extracts a blood vessel region from a three-dimensional medical image of a subject including a blood vessel, and a blood flow simulation unit that obtains a line resistance by multiplying a resistance value corresponding to a branch blood vessel branching out of the blood vessel region by a surface area of each of preset sections into which the blood vessel region is divided in an extension direction, generates a vascular network model by applying the line resistance to each node of a surface of the blood vessel region, and performs simulation of a blood flow by using the vascular network model.