A counter-rotating axial-flow fan comprising: a housing (5,59) including a housing body (11,65) having an air channel formed therein and a motor support frame (13,67) provided in a center portion of the air channel, the air channel having a suction port on one end and a discharge port on the other end in an axial direction; a first impeller arranged within a first space defined between the motor support frame (13,67) and the suction port in the housing (5,59) and including a plurality of blades; a first motor that rotates the first impeller within the first space in a first rotating direction; a second impeller arranged within a second space defined between the motor support frame (13,67) and the discharge port in the housing (5,59) and including a plurality of blades; and a second motor that rotates the second impeller within the second space in a second rotating direction which is opposite to the first rotating direction, the first and second motors (7,61) each having a rotary shaft (31,85), a stator (33,87), and a rotor (35,89) rotating around the stator (33,87), the motor support frame (13,67) including a support frame body (21,75) positioned in the center portion of the air channel and a plurality of webs (23A-23H,77A-77H) arranged between the support frame body (21,75) and the housing body (11,65) at predetermined intervals in a circumferential direction of the rotary shafts (31,85) so as to connect the support frame body (21,75) and the housing body (11,65), the first and second motors (7,61) being respectively arranged within the first and second spaces (S1,S2) such that axial lines of the rotary shafts (21,75) extend along a virtual center line connecting the center of the suction port and the center of the discharge port, the stator of the first motor and stator of the second motor being fixed onto the support frame body (21,75), characterised in that the first impeller and the rotor of the first motor are configured to introduce air sucked from the suction port into an internal space of the first motor, one or more through-holes (29A-29D,81A-81D) which penetrate the support frame body (21,75) in an extending direction of the axial line are formed in the support frame body (21,75); and positions and a total cross sectional area of the one or more through-holes (29A-29D,81A-81D) are defined to introduce the air, which has been introduced into the internal space of the first motor, into an internal space of the second motor so as to directly cool the stator of the first motor and the stator of the second motor. a housing (5,59) including a housing body (11,65) having an air channel formed therein and a motor support frame (13,67) provided in a center portion of the air channel, the air channel having a suction port on one end and a discharge port on the other end in an axial direction; a first impeller arranged within a first space defined between the motor support frame (13,67) and the suction port in the housing (5,59) and including a plurality of blades; a first motor that rotates the first impeller within the first space in a first rotating direction; a second impeller arranged within a second space defined between the motor support frame (13,67) and the discharge port in the housing (5,59) and including a plurality of blades; and a second motor that rotates the second impeller within the second space in a second rotating direction which is opposite to the first rotating direction, the first and second motors (7,61) each having a rotary shaft (31,85), a stator (33,87), and a rotor (35,89) rotating around the stator (33,87), the motor support frame (13,67) including a support frame body (21,75) positioned in the center portion of the air channel and a plurality of webs (23A-23H,77A-77H) arranged between the support frame body (21,75) and the housing body (11,65) at predetermined intervals in a circumferential direction of the rotary shafts (31,85) so as to connect the support frame body (21,75) and the housing body (11,65), the first and second motors (7,61) being respectively arranged within the first and second spaces (S1,S2) such that axial lines of the rotary shafts (21,75) extend along a virtual center line connecting the center of the suction port and the center of the discharge port, the stator of the first motor and stator of the second motor being fixed onto the support frame body (21,75), characterised in that the first impeller and the rotor of the first motor are configured to introduce air sucked from the suction port into an internal space of the first motor, one or more through-holes (29A-29D,81A-81D) which penetrate the support frame body (21,75) in an extending direction of the axial line are formed in the support frame body (21,75); and positions and a total cross sectional area of the one or more through-holes (29A-29D,81A-81D) are defined to introduce the air, which has been introduced into the internal space of the first motor, into an internal space of the second motor so as to directly cool the stator of the first motor and the stator of the second motor.