Medical device having rotating shaft with lumen and sealing structure

A medical device for removing an object inside a biological lumen, comprising:

• a drive shaft that is rotatable about a rotation axis;
• a cutting portion fixed to a distal portion of the drive shaft and configured to cut the object;
• a first housing that accommodates the drive shaft to be rotatable relative to the first housing;
• a second housing located on a distal side of the first housing and rotatable with respect to the first housing around the rotation axis, wherein the drive shaft is rotatable relative to the second housing;
• and
• a support portion that supports the first housing and the second housing, wherein the drive shaft is rotatable relative to the support portion,
• wherein one of the first housing, the second housing, and the support portion has a recess portion, and an other one of the first housing, the second housing, and the support portion has a projection portion fittable into and detachable from the recess portion by relatively moving along the rotation axis,
• wherein the projection portion and the recess portion are configured to be fitted together to restrict relative rotation of the first housing and the second housing,
• wherein the support portion supports at least one of the first housing and the second housing to be rotatable around the rotation axis.