A vehicle side airbag device includes a side airbag, an inner tether that extends in the seat forward direction at the seat width direction inner side of the side airbag in the inflated and deployed state and has a distal end portion anchored to the side airbag, and an outer tether that extends outward in the seat width direction from the seat rear side of the side airbag in the inflated and deployed state and has a distal end portion anchored to the side airbag. An upper end portion of the distal end portion of the outer tether is positioned further toward an upper end side of the side airbag than an upper end portion of the distal end portion of the inner tether.