An image coding method includes: writing, to a memory, a first motion vector for a first sub-block; reading, from the memory, the first motion vector; coding a second motion vector for a second sub-block, using the first motion vector; selecting a representative motion vector from among motion vectors for sub-blocks; determining whether or not the representative motion vector is used in place of the first motion vector; and adding, to a bitstream, a flag indicating whether or not the representative motion vector is used, wherein when the representative motion vector is used: in the writing, the representative motion vector is written to the memory; in the reading, the representative motion vector is read from the memory; and in the coding, the second motion vector is coded using the representative motion vector.