A catheter assembly includes: a catheter； a catheter hub connected to the catheter； an inner needle removably disposed in the catheter； a needle hub connected to the inner needle； and a deflection suppressing member that suppresses deflection of the inner needle by supporting the inner needle via the catheter at a location distal of the catheter hub. The deflection suppressing member is supported so as to be movable relative to the needle hub in an axial direction.
