A motor device includes a motor, a first substrate, a second substrate, a first heat sink, and a second heat sink. The second substrate is placed to face the first substrate in the plate-thickness direction of the second substrate. A second element group provided on the second substrate has a heat generation amount larger than that of a first element group provided on the first substrate. The first heat sink is placed between the first substrate and the second substrate so as to promote heat dissipation from the first element group and the second element group. The second heat sink is placed on the opposite side of the second substrate from the first heat sink and is configured to promote heat dissipation from the second element group.