A motor for a vehicle, comprising: a rotor shaft rotating around an axis and having opposed axial ends; a rotor iron core fixed to the rotor shaft; a stator iron core disposed radially outside of the rotor iron core; a casing accommodating the rotor iron core and the stator iron core therein, and supporting the opposed axial ends of the rotor shaft via bearings (33A, 33B) such that the rotor shaft is rotatable; an air inlet port (55, 56) formed in a portion of the casing radially spaced from the bearing (33A, 33B); and a fan provided between the rotor iron core and the bearing (33A, 33B) and rotating with the rotor shaft to introduce outside air into the air inlet port (55, 56), wherein the casing includes a pair of annular bearing housings (41A, 41 B) disposed around the pair of the bearings (33A, 33B) in the radial direction, and a pair of connecting housing portions (65, 66) cylindrically shaped to surround the rotor shaft from the outside in the radial direction and connecting between the bearing housings (41A, 41B) and iron core supporting members, a portion of the casing positioned outside impellers of the fan in the axial direction forms a first connecting housing portion and a second connecting housing portion constituting a discharge channel through which the outside air is discharged, the first connecting housing portion comprises a guide wall extending in the radial direction, wherein the second connecting housing portion comprises a thin wall portion having a thinner wall thickness than that of adjacent portions of the second connecting housing portion spaced from the guide wall in the axial direction to constitute the discharge channel between the thin wall portion and the guide wall, wherein each of the guide wall and the thin wall portion is provided in the circumferential direction in such a manner that the discharge channel is formed and extends in the circumferential direction to form an entrance port and an exit port thereof, and the guide wall and the thin wall portion approach each other in the direction from the entrance port to the exit port of the discharge channel. a rotor shaft rotating around an axis and having opposed axial ends; a rotor iron core fixed to the rotor shaft; a stator iron core disposed radially outside of the rotor iron core; a casing accommodating the rotor iron core and the stator iron core therein, and supporting the opposed axial ends of the rotor shaft via bearings (33A, 33B) such that the rotor shaft is rotatable; an air inlet port (55, 56) formed in a portion of the casing radially spaced from the bearing (33A, 33B); and a fan provided between the rotor iron core and the bearing (33A, 33B) and rotating with the rotor shaft to introduce outside air into the air inlet port (55, 56), wherein the casing includes a pair of annular bearing housings (41A, 41 B) disposed around the pair of the bearings (33A, 33B) in the radial direction, and a pair of connecting housing portions (65, 66) cylindrically shaped to surround the rotor shaft from the outside in the radial direction and connecting between the bearing housings (41A, 41B) and iron core supporting members, a portion of the casing positioned outside impellers of the fan in the axial direction forms a first connecting housing portion and a second connecting housing portion constituting a discharge channel through which the outside air is discharged, the first connecting housing portion comprises a guide wall extending in the radial direction, wherein the second connecting housing portion comprises a thin wall portion having a thinner wall thickness than that of adjacent portions of the second connecting housing portion spaced from the guide wall in the axial direction to constitute the discharge channel between the thin wall portion and the guide wall, wherein each of the guide wall and the thin wall portion is provided in the circumferential direction in such a manner that the discharge channel is formed and extends in the circumferential direction to form an entrance port and an exit port thereof, and the guide wall and the thin wall portion approach each other in the direction from the entrance port to the exit port of the discharge channel.