An image decoding method performed by a decoding apparatus, according to the present document, comprises the steps of: acquiring syntax elements for a first transform coefficient through an n-th transform coefficient of a current block, wherein the syntax elements are syntax elements according to a first residual data coding structure of TSRC; and acquiring syntax elements for an n+1st transform coefficient through a last transform coefficient of the current block, wherein the syntax elements are syntax elements according to a second residual data coding structure of the TSRC, wherein the number of context-coded syntax elements for the first transform coefficient through the n-th transform coefficient is equal to the maximum number of context-coded bins of the current block, and the syntax elements according to the second residual data coding structure include coefficient level information and a sign flag for a transform coefficient.