SEAT DEVICE

A seat device () that can reliably and easily regulate a reclining operation with a simple and compact configuration, only in a specific state where the reclining operation of a seat () is problematic. It includes a reclining operation unit () that performs an operation of tilting a backrest () of the seat () by a reclining mechanism (), a lock mechanism () that restrains the reclining operation unit () to disable the operation when the seat () is in a long state, and a cable () that is pulled in conjunction with conversion into the long state of the seat (). The lock mechanism () includes a stopper () that is linearly moved to be engaged with and released from an operation lever () of the reclining operation unit (), and the stopper () is directly pulled by the cable () to be linearly moved to a restrained position at which the stopper () is engaged with the operation lever () to disable the operation.