A picture coding device configured to partition difference information between a picture serving as a coding target and a picture serving as a prediction target into a plurality of sub blocks, and codes the partitioned sub block in a certain order, the picture coding device comprising: a significant sub block information encoder (706, 708, 701) configured to code significant sub block information indicating whether or not all values of difference coefficients belonging to the sub block serving as the coding target are zero; a significant difference coefficient information encoder (706, 708) configured to code significant difference coefficient information indicating whether or not each value of difference coefficient at each position of difference coefficient serving as the coding target is zero; a difference coefficient value encoder (707, 701) configured to code value of difference coefficient serving as the coding target; and a context deriver (707, 701) configured to derive a context for coding the significant difference coefficient information based on sum of vertical position of the difference coefficient and horizontal position of the difference coefficient in sub block serving as the coding target, and either of 1) sum of significant sub block information of coded sub block neighboring the sub block serving as the coding target at right side and lower side, 2) sum of significant difference coefficient information of difference coefficients neighboring the sub block serving as the coding target at right side and lower side, or 3) sum of absolute value of difference coefficients neighboring the sub block serving as the coding target at right side and lower side, when the sum of significant difference coefficient information is equal to 0 or 1, set an index of the context to 0 or 1 according to the sum of vertical position of the difference coefficient and horizontal position of the difference coefficient in sub block serving as the coding target, when the sum of significant difference coefficient information is equal to 2, set the context index to 1 or 2 according to the sum of vertical position of the difference coefficient and horizontal position of the difference coefficient in sub block serving as the coding target, when the sum of significant difference coefficient information is greater than 2, set the context index to 2. a significant sub block information encoder (706, 708, 701) configured to code significant sub block information indicating whether or not all values of difference coefficients belonging to the sub block serving as the coding target are zero; a significant difference coefficient information encoder (706, 708) configured to code significant difference coefficient information indicating whether or not each value of difference coefficient at each position of difference coefficient serving as the coding target is zero; a difference coefficient value encoder (707, 701) configured to code value of difference coefficient serving as the coding target; and a context deriver (707, 701) configured to derive a context for coding the significant difference coefficient information based on sum of vertical position of the difference coefficient and horizontal position of the difference coefficient in sub block serving as the coding target, and either of 1) sum of significant sub block information of coded sub block neighboring the sub block serving as the coding target at right side and lower side, 2) sum of significant difference coefficient information of difference coefficients neighboring the sub block serving as the coding target at right side and lower side, or 3) sum of absolute value of difference coefficients neighboring the sub block serving as the coding target at right side and lower side, when the sum of significant difference coefficient information is equal to 0 or 1, set an index of the context to 0 or 1 according to the sum of vertical position of the difference coefficient and horizontal position of the difference coefficient in sub block serving as the coding target, when the sum of significant difference coefficient information is equal to 2, set the context index to 1 or 2 according to the sum of vertical position of the difference coefficient and horizontal position of the difference coefficient in sub block serving as the coding target, when the sum of significant difference coefficient information is greater than 2, set the context index to 2.