The panel-like formed product includes a polygonal top board, two or more vertical walls, and a flange. The vertical walls extend from two or more sides of the top board, and include at least two adjacent vertical walls extending from at least two adjacent sides of the top board. The top board includes a frame portion, and a concave portion which is located at an inner side of the frame portion. The two or more adjacent vertical walls include a first vertical wall section, a stair, and a second vertical wall section. The stair connects to a lower end of the first vertical wall section. The second vertical wall section connects to an outer edge of the stair. The flange connects to a lower end of the second vertical wall section.