Provided is a plastic foamed article to be attached to an attaching target having a rod-shaped attaching portion having a radial direction, the plastic foamed article including a holding portion for holding the attaching portion in the radial direction in a state attached to the attaching target, the holding portion including a pair of opposite surfaces facing each other for holding the attaching portion between the pair of opposite surfaces and a protrusion provided on one of the pair of opposite surfaces, and at least a part of the protrusion is configured to be elastically deformed by the attaching portion in a state in which the attaching portion is held between the pair of opposite surfaces.