Abstract: The invention provides a part mounting clamp in which an engaging piece is reliably and sufficiently engaged with a mounting hole peripheral portion by conventional general inserting operation even under a condition where a burr exists on a mounting hole of an attaching subject, and excellent attached state can be obtained. To this end, in an insertion-engagement type attaching clamp, the engaging step 9 includes a vertical wall 9t abutting against an inner peripheral surface 3n of the mounting hole 3 of the sheet metal panel 2, and a lateral wall 9y extending along an outer surface 2A of the mounting hole peripheral portion 2a of the sheet metal panel 2. The engaging step 9 is formed such that in an attached state, a contained angle between the lateral wall 9y and the outer surface 2A becomes 5°.