A side airbag of a far side airbag device includes a rear inflation section that inflates and deploys on being supplied with gas and restrains at least rear portions of the chest and abdominal regions of a seated occupant, and a front inflation section that inflates and deploys by being supplied with gas through a through hole formed at a boundary between the rear inflation section and the front inflation section to restrain at least front portions of the chest and abdominal regions of the seated occupant. The far side airbag device includes a tension member that, on receiving tension and adopting a deployed state accompanying inflation and deployment of the side airbag, has a front end side connected to the rear inflation section, and a rear end side connected to a seatback frame.