A medical device is able to achieve a high aspiration pressure while also effectively transmitting rotational torque to a cutting portion to remove an object inside a biological lumen. The medical device includes a drive shaft, an outer tube accommodating the drive shaft, a cutting portion fixed to the drive shaft, and a hub unit. The hub unit has a first housing with an aspiration port, a second housing with a liquid delivering port, and first and second seal portions disposed between the second housing and the drive shaft. The first seal portion has a first frictional coefficient, and the second seal portion has a second frictional coefficient. The first frictional coefficient is lower than the second frictional coefficient, and the first seal portion is located on a distal side of the second seal portion.