To provide a retractable vehicular seat device capable of rotatably moving a seat positioned in one of a storing position and a using position to the other position by a small force and capable of preventing the seat reaching the storing position or the using position from being crashed into a vehicular floor face violently.

One end SP2 of a torsion coil spring SP is engaged with a support 28b formed in a base member 28 in a non-rotatable state around an axis of the torsion coil spring, and the other end SP3 of the torsion coil spring SP is positioned between a first locking part 34c and a second locking part 34d formed in a connection bracket 34 in a rotatable state around the axis.