A seat reclining device includes: a reclining unit that includes a fixing member fixed to a seat cushion side and a rotating member fixed to the seat cushion side and supported by the fixing member to rotate freely, and that switches freely between a locked state and an unlocked state; a transmission lever supported by the fixing member to rotate freely on the same center as the fixing member; a release operation lever supported on the seat cushion side to rotate freely between lock operation and unlocking operation positions; a link which includes a protruding portion, in which each end portion of the link is supported by one of the transmission and release operation levers to rotate freely, and which switches the reclining unit from the locked state to the unlocked state; and a holding plate that includes an unlock holding portion.