A moving image reencoding device, includes a processor; and a memory which stores a plurality of instructions, which when executed by the processor, cause the processor to execute, decoding encoded moving image data that is encoded by a first encoding method that enables switching for a frame encoding mode in which encoding is performed on the basis of a frame or a field encoding mode in which encoding is performed on the basis of a field, in a block unit that is obtained by dividing a picture, and acquiring importance degree information related to an importance degree of an encoding mode that is switched in the block unit, when decoding the encoded moving image data; acquiring an encoding parameter that is set as a second encoding method, the second encoding method enabling switching for the frame encoding mode or the field encoding mode in a picture unit, or statistical information.