Snap ring attachment and snap ring attaching tool

A snap ring attachment that attaches a C-type snap ring having a gap to an attachment groove of a workpiece, comprising:

• a guide cylinder that defines a guide path having a region of a supply port side, to which the snap ring is supplied, having a circular cross section and a region of an exit side, from which the snap ring is pushed out, having an elliptic cross section, the circular cross section continuously varying to the elliptic cross section, in order to guide the snap ring toward the attachment groove;
• a posture changing and pressing mechanism arranged in the guide cylinder so as to press the snap ring supplied in an upright state vertical to an extending direction of the guide path while being radially contracted, move while inclining the snap ring, then again erect the snap ring, and press the snap ring while changing a posture of the snap ring to be pushed into the attachment groove;
• and
• a driving mechanism that exerts driving force to generate pressing force in the posture changing and pressing mechanism.