An electric motor, comprising: a rotatable motor shaft; a rotor rotatable integrally with the motor shaft about an axis of the motor shaft; a stator arranged around the rotor to rotate the rotor; a box-shaped housing body which is open at the top thereof and accommodates the rotor and the stator; and an end cover attached to the housing body to close the top opening of the housing body, where the housing body and the end cover constitute a housing that rotatably supports the motor shaft, wherein the housing body is internally formed with a cooling channel which allows refrigerant to flow therein, wherein: the stator has an outer peripheral surface including a plurality of projections projecting radially outward at respective positions arranged circumferentially; the housing body has an inner peripheral surface including a plurality of recesses fitted with the projections, respectively, and holds the stator in a state of respective fits of the projections with the recesses; and the cooling channel includes a plurality of main channels that are formed in respective inter-recess regions defined between circumferentially adjacent recesses, and a connection channel located at a position axially shifted from a recess and crossing the recess to interconnect main channels adjacent across the recess, characterized in that the housing body is internally formed with the cooling channel including the main channels and the connection channel, each of the plurality of connection channels is located at a position shifted from the recess axially of the electric motor and extends circumferentially across the recess such that at least a part of the connection channel overlaps the recess when seen axially of the electric motor. a rotatable motor shaft; a rotor rotatable integrally with the motor shaft about an axis of the motor shaft; a stator arranged around the rotor to rotate the rotor; a box-shaped housing body which is open at the top thereof and accommodates the rotor and the stator; and an end cover attached to the housing body to close the top opening of the housing body, where the housing body and the end cover constitute a housing that rotatably supports the motor shaft, wherein the housing body is internally formed with a cooling channel which allows refrigerant to flow therein, wherein: the stator has an outer peripheral surface including a plurality of projections projecting radially outward at respective positions arranged circumferentially; the housing body has an inner peripheral surface including a plurality of recesses fitted with the projections, respectively, and holds the stator in a state of respective fits of the projections with the recesses; and the cooling channel includes a plurality of main channels that are formed in respective inter-recess regions defined between circumferentially adjacent recesses, and a connection channel located at a position axially shifted from a recess and crossing the recess to interconnect main channels adjacent across the recess, characterized in that the housing body is internally formed with the cooling channel including the main channels and the connection channel, each of the plurality of connection channels is located at a position shifted from the recess axially of the electric motor and extends circumferentially across the recess such that at least a part of the connection channel overlaps the recess when seen axially of the electric motor. the stator has an outer peripheral surface including a plurality of projections projecting radially outward at respective positions arranged circumferentially; the housing body has an inner peripheral surface including a plurality of recesses fitted with the projections, respectively, and holds the stator in a state of respective fits of the projections with the recesses; and the cooling channel includes a plurality of main channels that are formed in respective inter-recess regions defined between circumferentially adjacent recesses, and a connection channel located at a position axially shifted from a recess and crossing the recess to interconnect main channels adjacent across the recess, characterized in that the housing body is internally formed with the cooling channel including the main channels and the connection channel, each of the plurality of connection channels is located at a position shifted from the recess axially of the electric motor and extends circumferentially across the recess such that at least a part of the connection channel overlaps the recess when seen axially of the electric motor.