The technology provides vehicle wheel disks where a spoke portion can have a spoke bottom wall and a spoke side portion. The spoke side portion can include a spoke side wall rising from the spoke bottom wall in an axial direction of the wheel and a spoke reinforcing wall connected from an axially end portion of the spoke side wall and curved from the axial direction of the wheel toward a circumferential direction of the wheel and extending in the circumferential direction of the wheel. A pair of spoke side portions can be located on opposite sides of the vent window in the circumferential direction of the wheel have radially inner end portions which are connected to each other via a connecting wall. The connecting wall can be flat or substantially flat in the circumferential direction of the wheel.