This upper body (30) comprises: a bearing seat face (50) that is fixed on the upper surface of a slewing bearing (5) by means of a bearing bolt; a slewing frame (40) that includes intersecting side plates (42) intersecting with the bearing seat face (50), and that is fixed to the bearing seat face (50); and a force dispersion member (60). The force dispersion member (60) includes at least one vertical plate (63) that extends in the vertical direction. Said at least one vertical plate (63) is fixed in a region of the bearing seat face (50) other than a region (55) where force is to be dispersed.
