A multiple ROI (region of interest) setting method and apparatus in scalable video coding and an ROI reconstructing method and apparatus are provided. The multiple ROI setting apparatus includes: an ROI setting unit which sets at least one or more R Ols and allocates ROI identification numbers to the each of ROIs; a mapping unit which allocates at least one or more slice group identification numbers to the at least one or more ROI identification numbers; and a message generating unit which generates a me ssage including ROI-associated information, slice-group-associated information, mappi ng information on mapping of the ROI identification number to the at least one or more slice group identification numbers, and scalability information.