A medical device and a treatment method capable of effectively suppressing an inflow of a contrast agent injected into blood vessels into kidney are provided. The medical device for suppressing an inflow of a contrast agent into kidney can include: an elongated inner tube, and a discharging portion configured to be capable of discharging a fluid in a proximal direction from both sides of a distal portion of the inner tube with an axial center being interposed therebetween, wherein the discharging portion includes a plurality of discharging holes arranged in one direction.
