Contour detection device for plastic pieces

The utility model provides a contour detection device for plastic pieces, which is applied in the detection technical field of automobile parts. The contour detection device comprises a base (1) and a plastic piece positioning unit (2) arranged on the base (1). The outer side of the plastic piece positioning unit (2) is provided with detection retaining pieces (3) in clearance arrangement at the outer ring of the plastic piece positioning unit (2). When a plastic piece (4) is placed on the plastic piece positioning unit (2) for being detected, a structure with equal clearances is arranged between the outer ring of the plastic piece (4) and the inner ring of the detection retaining pieces (3). The detection device also comprises a detection pen (5) for detecting whether all the clearances between the outer ring of the plastic piece (4) and the inner ring of the detection retaining pieces (3) are equal to each other or not. The contour detection device for plastic pieces accelerates the detection speed and effe