Technology for improving coding efficiency by performing a block split suitable for picture coding and decoding is provided. A device includes a coding information storage unit configured to fill all history-based candidates in a history-based motion vector predictor candidate list with at least predetermined motion vector and reference index; a merging candidate list generation unit configured to generate a merging candidate list including at least a motion vector and a reference index of a block neighboring a coding target block as a merging candidate; a history-based merging candidate addition unit configured to add a history-based candidate included in the history-based motion vector predictor candidate list to the merging candidate list as a merging candidate and output a second merging candidate list; and a merging candidate selection unit configured to select a merging candidate from the second merging candidate list as a selection merging candidate, wherein the coding information storage unit adds the selection merging candidate to the history-based motion vector predictor candidate list as a history-based candidate and outputs the history-based motion vector predictor candidate list.