PURPOSE: To provide a part grasping device which can surely comprehend whether the posture of a part grasped by a part grasping hand is proper or not.

CONSTITUTION: In a part attaching device which has a part grasping hand formed of at least a pair of claw members 23 arranged relatively movably around an adsorbing nozzle 16, and makes the claw member 23 approach a plate-shaped part P absorbedly held by the adsorbing nozzle 16 for positioning the part P, and judges the propriety of a part grasping posture from back pressure acting on the adsorbing nozzle 16, when the part P is held by either of a pair of claw members 23 in the abnormal posture of the part laterally drawn to the adsorbing nozzle 16, an auxiliary claw 35 to engage a part in precedence of a claw member on the other side is provided, and an equipment is inclined by the auxiliary claw 35 to open the opening 16a of the adsorbing nozzle 16.