Abstract: Provided are motion information encoding/decoding apparatus and method and scalable video encoding/decoding apparatus and method employing the same. The motion information encoding apparatus includes a first motion estimation unit, a second motion estimation unit, and an encoding unit. The first motion estimation unit generates base motion data for a layer corresponding to a low bit rate among a plurality of layers by performing motion estimation in units of a first block and generates enhancement data for the layer corresponding to the low bit rate by performing motion estimation in units of a second block. The second motion estimation unit generates motion data for the layer having the higher bit rate by performing motion estimation. The encoding unit performs encoding on the base motion data and the enhancement motion data provided from the first motion estimation unit or the motion data provided from the second motion estimation unit.