An error correction device, comprising: an error correction encoding unit configured to multi-level encode a sequence to be transmitted with only one type of LDPC convolutional code, wherein the error correction device is configured to transmit the encoded sequence using a multi-level modulation and an error rate differs for each bit or bit group forming each multi-level modulation symbol; and an error correction decoding unit configured to decode a received sequence multi-level encoded with the one type of LDPC convolutional code, wherein the error correction encoding unit is further configured to perform encoding processing for the sequence to be transmitted based on a check matrix of the one type of LDPC convolutional code having one type of redundancy and code length, wherein the error correction decoding unit is further configured to perform decoding processing for the received sequence based on the check matrix of the one type of LDPC convolutional code, wherein the check matrix of the one type of LDPC convolutional code includes a plurality of check submatrices combined with each other in an LDPC rule structure, wherein the decoding processing includes windowed decoding processing of sequentially performing decoding in units of windows by using a window including, at least partially, one or more check submatrices, wherein the windowed decoding processing is repeatedly executed by a number of times corresponding to a decoding iteration count, wherein a window size of the window and the decoding iteration count are configured to be variable depending on a throughput input to the error correction decoding unit, and wherein the window size and the decoding iteration count are input from an external control circuit connected to the error correction decoding unit, and wherein the control circuit is configured to determine the window size and the decoding iteration count in accordance with an error rate of each bit of a multi-level modulation symbol forming the received sequence, and the throughput input to the error correction decoding unit. an error correction encoding unit configured to multi-level encode a sequence to be transmitted with only one type of LDPC convolutional code, wherein the error correction device is configured to transmit the encoded sequence using a multi-level modulation and an error rate differs for each bit or bit group forming each multi-level modulation symbol; and an error correction decoding unit configured to decode a received sequence multi-level encoded with the one type of LDPC convolutional code, wherein the error correction encoding unit is further configured to perform encoding processing for the sequence to be transmitted based on a check matrix of the one type of LDPC convolutional code having one type of redundancy and code length, wherein the error correction decoding unit is further configured to perform decoding processing for the received sequence based on the check matrix of the one type of LDPC convolutional code, wherein the check matrix of the one type of LDPC convolutional code includes a plurality of check submatrices combined with each other in an LDPC rule structure, wherein the decoding processing includes windowed decoding processing of sequentially performing decoding in units of windows by using a window including, at least partially, one or more check submatrices, wherein the windowed decoding processing is repeatedly executed by a number of times corresponding to a decoding iteration count, wherein a window size of the window and the decoding iteration count are configured to be variable depending on a throughput input to the error correction decoding unit, and wherein the window size and the decoding iteration count are input from an external control circuit connected to the error correction decoding unit, and wherein the control circuit is configured to determine the window size and the decoding iteration count in accordance with an error rate of each bit of a multi-level modulation symbol forming the received sequence, and the throughput input to the error correction decoding unit.