An error correction decoding apparatus includes column operators 201 and row operators 211 to 213 provided respectively in accordance with the columns and rows of a check matrix of an LDPC code. A received LLR (log-likelihood ratio) of a received sequence is input into the column operators 201 together with row LLRs from the row operators 211 to 213, whereupon the column operators 201 calculate a total value z1 of the received LLR of the received sequence and the row LLRs from the row operators 211 to 213. The row operators 211 to 213 hold operation results relating to row LLRs or column LLRs obtained during a previous operation, calculate column LLRs using the total value input from the column operators 201 and the held operation results, calculate row LLRs from the calculated column LLRs, and output the calculated row LLRs to the column operators 201.