A vehicle wheel disk includes a plurality of spoke portions extending radially outwardly from a hub coupling portion with vent windows between the spokes. Each spoke includes a bottom wall and axially extending side walls, with a radially outer disk portion connecting the radially outer ends of the spokes. A connecting wall connects a pair of spoke side portions on opposite sides of the vent window in the circumferential direction of the wheel. The spoke bottom wall includes an axially extending inclined portion and a radially extending main portion. A spoke strengthening wall extends circumferentially from the axial end of the spoke side wall. The connecting wall includes a vent window surrounding portion, a vent window surrounding curved portion, and a crest wall portion of a radially inwardly protruding protrusion.