A vehicle-mounted apparatus, comprising: a motor unit comprising a drive motor and a speed reducer configured to reduce a speed of rotation of an output shaft of the drive motor, the motor unit being configured to apply a rotational driving force to a wheel of a vehicle; and a friction brake for reducing the rotation of the wheel, wherein the friction brake comprises: at least one rotation disc for rotating integrally with the output shaft of the drive motor; a housing that is a non-rotatable member; at least one friction plate (32, 34) held by the housing so as to be movable relative to the housing in an axial direction that is a direction of an axis parallel with a rotation axis of the wheel such that rotation of the at least one friction plate (32, 34) relative to the housing about the axis is restricted; and a pressing device (38; 100) configured to press the at least one friction plate (32, 34) against the at least one rotation disc, wherein the housing comprises a first housing having a substantially cylindrical shape having a closed bottom, wherein the first housing comprises a cylindrical portion and a bottom portion, wherein the pressing device (38; 100) is held by the first housing, the vehicle-mounted apparatus being characterised in that at least one rim is provided at the bottom portion of the first housing. a motor unit comprising a drive motor and a speed reducer configured to reduce a speed of rotation of an output shaft of the drive motor, the motor unit being configured to apply a rotational driving force to a wheel of a vehicle; and a friction brake for reducing the rotation of the wheel, wherein the friction brake comprises: at least one rotation disc for rotating integrally with the output shaft of the drive motor; a housing that is a non-rotatable member; at least one friction plate (32, 34) held by the housing so as to be movable relative to the housing in an axial direction that is a direction of an axis parallel with a rotation axis of the wheel such that rotation of the at least one friction plate (32, 34) relative to the housing about the axis is restricted; and a pressing device (38; 100) configured to press the at least one friction plate (32, 34) against the at least one rotation disc, at least one rotation disc for rotating integrally with the output shaft of the drive motor; a housing that is a non-rotatable member; at least one friction plate (32, 34) held by the housing so as to be movable relative to the housing in an axial direction that is a direction of an axis parallel with a rotation axis of the wheel such that rotation of the at least one friction plate (32, 34) relative to the housing about the axis is restricted; and a pressing device (38; 100) configured to press the at least one friction plate (32, 34) against the at least one rotation disc, wherein the housing comprises a first housing having a substantially cylindrical shape having a closed bottom, wherein the first housing comprises a cylindrical portion and a bottom portion, wherein the pressing device (38; 100) is held by the first housing, the vehicle-mounted apparatus being characterised in that at least one rim is provided at the bottom portion of the first housing.