A seat reclining apparatus for a vehicle, includes the pair of lower arms each connected to the lower side frame, the upper arm positioned between the pair of lower arms and fixedly attached to the upper side frame, the pair of recliners joined to the upper arm and to the pair of lower arms, the electric motor, the lower side frame provided as a pair for sandwiching the pair of lower arms and connected to the pair of lower arms in a manner that the pair of lower arms is pivotable relative to the lower side frame, and a lock member for engaging with the pair of lower side frames and with the pair of lower arms for restricting a relative pivoting movement between the pair of lower side frames and the pair of lower arms in a state where a relative pivot angle therebetween is at a predetermined angle.