A medical device for cutting substances inside a body lumen includes a flexible and elongated drive shaft including a distal portion and a proximal portion, a cutting member connected to the distal portion of the drive shaft to be rotatable with the drive shaft, and a hub located at the proximal portion and supporting the drive shaft, the hub including a first bearing mounted on the drive shaft and an elastic ring that is made of an elastic material on an outer periphery of the first bearing.