A decoding method for decoding a control parameter for controlling decoding of an image, the decoding method comprising: determining a context for a current block in the image, from among a plurality of contexts; and performing arithmetic decoding on a bitstream corresponding to the current block, using the determined context to obtain a control parameter for the current block, the control parameter being used for decoding the current block; wherein the determining further includes: determining a syntax element corresponding to the control parameter for the current block; determining the context by using both of decoded control parameters for a left block and an upper block, when a context type of the syntax element is categorized in a first type; determining the context by using a predetermined fixed value, when the context type is categorized in a second type; and determining the context by using a hierarchical depth of a data unit to which the control parameter for the current block belongs, when the context type is categorized in a third type; wherein the left block is a neighboring block to the left of the current block, and the upper block is a neighboring block on top of the current block; the second type is different from the first type, and the third type is different from the first type and the second type; one of a split flag and a skip flag is categorized in the first type; a merge flag and chroma intra prediction mode are categorized in the second type; and a first coefficient flag (cbf_luma), and a second coefficient flag (cbf_cb, cbf_cr) are categorized in the third type; wherein the split flag indicates whether or not the current block is partitioned into a plurality of blocks, and the skip flag indicating whether or not the current block is to be skipped; the merge flag indicates whether or not a merge mode is used to predict the current block, wherein the current block is decoded based on a prediction using a motion vector and a reference picture index which are copied from a neighboring block in the merge mode, and the chroma intra prediction mode being used for intra prediction for chroma of the current block; the first coefficient flag (cbf_luma) and the second coefficient flag (cbf_cb, cbf_cr) indicate the presence or absence of coefficients of luma or chroma; and the total number of contexts of the second coefficient flag (cbf_cb, cbf_cr) is less than the total number of contexts of the first coefficient flag (cbf_luma). determining a context for a current block in the image, from among a plurality of contexts; and performing arithmetic decoding on a bitstream corresponding to the current block, using the determined context to obtain a control parameter for the current block, the control parameter being used for decoding the current block; wherein the determining further includes: determining a syntax element corresponding to the control parameter for the current block; determining the context by using both of decoded control parameters for a left block and an upper block, when a context type of the syntax element is categorized in a first type; determining the context by using a predetermined fixed value, when the context type is categorized in a second type; and determining the context by using a hierarchical depth of a data unit to which the control parameter for the current block belongs, when the context type is categorized in a third type; wherein determining a syntax element corresponding to the control parameter for the current block; determining the context by using both of decoded control parameters for a left block and an upper block, when a context type of the syntax element is categorized in a first type; determining the context by using a predetermined fixed value, when the context type is categorized in a second type; and determining the context by using a hierarchical depth of a data unit to which the control parameter for the current block belongs, when the context type is categorized in a third type; wherein the left block is a neighboring block to the left of the current block, and the upper block is a neighboring block on top of the current block; the second type is different from the first type, and the third type is different from the first type and the second type; one of a split flag and a skip flag is categorized in the first type; a merge flag and chroma intra prediction mode are categorized in the second type; and a first coefficient flag (cbf_luma), and a second coefficient flag (cbf_cb, cbf_cr) are categorized in the third type; wherein the split flag indicates whether or not the current block is partitioned into a plurality of blocks, and the skip flag indicating whether or not the current block is to be skipped; the merge flag indicates whether or not a merge mode is used to predict the current block, wherein the current block is decoded based on a prediction using a motion vector and a reference picture index which are copied from a neighboring block in the merge mode, and the chroma intra prediction mode being used for intra prediction for chroma of the current block; the first coefficient flag (cbf_luma) and the second coefficient flag (cbf_cb, cbf_cr) indicate the presence or absence of coefficients of luma or chroma; and the total number of contexts of the second coefficient flag (cbf_cb, cbf_cr) is less than the total number of contexts of the first coefficient flag (cbf_luma).