Provided is a guide roller for a vehicular slide door. The guide roller has an annular metal inner ring; a retainer holding a bearing; an annular metal outer ring and a sliding layer including a synthetic resin. When the sliding layer is sectionalized into a sliding surface side area, an intermediate area and an interface side area, from the sliding surface to an interface with the outer ring, the synthetic resins in the sliding surface side area, the intermediate area and the interface side area have, respectively, a degree of crystallizations X1, X2 and X3 and nanoindenter hardnesses Y1, Y2 and Y3 wherein X2−X1 is less than 5%, and X2−X3 is less than 5% and wherein Y2 is not less than 115% of Y1, and Y2 is not less than 115% of Y3.