A catheter assembly including a catheter； a catheter hub fixed to a proximal end portion of the catheter； an inner needle disposed inside the catheter； and a housing supporting the inner needle, the housing accommodating the catheter hub when in an initial state in which a distal end of the inner needle is protruding from a distal end of the catheter. The catheter hub is configured to rotate with respect to the inner needle and the housing when accommodated inside the housing.
