An outdoor unit of an air conditioner, wherein the outdoor unit is an upper discharge type outdoor unit comprising: a blower configured to flow air; a heat exchanger disposed upstream of the blower in the direction of airflow; and a housing configured to accommodate the blower and the heat exchanger, wherein the blower comprises a fan, a motor driving the fan, a leg portion in contact with the motor, and a motor support member disposed upstream of the fan on a flow path, through which air generated by a rotation of the fan, flows, wherein the motor support member is fixed to the leg portion and configured to support the motor through the leg portion, wherein the motor support member comprises a cross-sectional shape comprising a maximum width portion having a maximum width in a direction perpendicular to the airflow direction, an upstream portion having a width that increases from the upstream side to the downstream side, and a downstream portion having a width that reduces from the upstream side to the downstream side, wherein a width of a downstream end of the downstream portion has a linear shape in a direction perpendicular to the airflow direction, and the width is formed in such a manner that the middle of a wing-shaped reduction portion is cut out in a plane substantially perpendicular to a rotating shaft of the fan, wherein a ratio of the downstream end width (W 1) of the downstream portion to the maximum width is linked with the ratio between a downstream portion length and an upstream portion length, and wherein the ratio of the downstream end width to the maximum width is equal to or greater than 0.86 and equal to or less than 0.94. a blower configured to flow air; a heat exchanger disposed upstream of the blower in the direction of airflow; and a housing configured to accommodate the blower and the heat exchanger, wherein the blower comprises a fan, a motor driving the fan, a leg portion in contact with the motor, and a motor support member disposed upstream of the fan on a flow path, through which air generated by a rotation of the fan, flows, wherein the motor support member is fixed to the leg portion and configured to support the motor through the leg portion, wherein the motor support member comprises a cross-sectional shape comprising a maximum width portion having a maximum width in a direction perpendicular to the airflow direction, an upstream portion having a width that increases from the upstream side to the downstream side, and a downstream portion having a width that reduces from the upstream side to the downstream side, wherein a width of a downstream end of the downstream portion has a linear shape in a direction perpendicular to the airflow direction, and the width is formed in such a manner that the middle of a wing-shaped reduction portion is cut out in a plane substantially perpendicular to a rotating shaft of the fan, wherein a ratio of the downstream end width (W 1) of the downstream portion to the maximum width is linked with the ratio between a downstream portion length and an upstream portion length, and wherein the ratio of the downstream end width to the maximum width is equal to or greater than 0.86 and equal to or less than 0.94.