Thrust sliding bearing

A thrust sliding bearing made of synthetic resin comprising:

• an annular upper case that is attached to a body of a vehicle having a strut type suspension;
• and
• an annular lower case that is arranged under the upper case and rotatably slides around an axial center of the upper case,
• wherein a tubular dust cover, which covers a piston rod of the strut type suspension, is assembled to a lower portion of the lower case,
• the lower case includes a plurality of upper tongues for engaging with at least a case-side protrusion provided on an inner circumferential side of the upper case and a plurality of lower tongues for engaging with at least a cover-side protrusion provided on the outer circumferential side of the dust cover, and
• each of the lower tongues of the lower case protrude in a direction toward the axial center from an inner circumferential surface of a cylindrical portion provided in the lower case, and
• each of the upper tongues of the lower case protrude in the direction toward the axial center from the inner circumferential surface of the cylindrical portion provided in the lower case without overlapping any of the lower tongues in an axial direction.