Abstract: A seat for use in a vehicle, which is capable of being turned toward a door opening with a child seat, etc. attached thereto, thereby favorably sitting a child, etc. on the child seat, etc. A turning seat S2 is provided adjacently to a door opening K2 in a vehicle compartment and has a locking mechanism for locking a seat main body in a front-facing position or a rear-facing position. When a seat back 12 is tilted forward, the locking mechanism is released to enable turn of the seat main body. The turning seat S2 is arranged such that when lock of the seat main body is released with the seat back 12 held upright, and the seat main body is turned toward the door opening K2, turn stopping means operates to stop turn of the seat main body in a predetermined turning position in which the seat main body faces toward the door opening K2, and that the stopping operation with the turn stopping means is released when the seat back 12 is tilted forward.