Abstract: Displacement of a switching member in a first direction causes rolling elements of each pair to come out of engagement with an outer peripheral portion or an inner peripheral portion and form clearances therewith, resulting in an OFF state of a driving force transmission apparatus. Displacement of the switching member in a second direction causes a downstream one of the rolling elements of each pair in the direction of rotation to come into zero clearance engagement with the outer peripheral portion and the inner peripheral portion, with a clearance formed between an upstream one of the rolling elements of each pair and the outer peripheral portion or the inner peripheral portion, resulting in an ON state of the driving force transmission apparatus.