A vehicle air-conditioning apparatus comprising: a cold air flow channel in which cold air flows; a warm air flow channel in which warm air flows; a mixing chamber configured to mix the cold air and the warm air to create air-conditioning air; a cold air opening that opens between the cold air flow channel and the mixing chamber; a warm air opening that opens between the warm air flow channel and the mixing chamber; a first opening and a second opening that open the mixing chamber; a third opening that opens the mixing chamber configured to blow out the air-conditioning air from a position lower than the first opening and the second opening; a case including at least the cold air flow channel, the warm air flow channel, the mixing chamber, the cold air opening, the warm air opening, the first opening, the second opening, and the third opening; a mix door configured to adjust a ratio between an amount of the cold air flowing from the cold air opening into the mixing chamber and an amount of the warm air flowing from the warm air opening into the mixing chamber; air distribution doors (221, 231, 241) disposed in the mixing chamber or on the downstream thereof and configured to regulate a flow of the air-conditioning air from the mixing chamber to the first, second, and third openings; and a rectifying portion disposed in the vicinity of an upstream end of the mixing chamber and configured to rectify the warm air flowing from the warm air opening into the mixing chamber toward the third opening, characterized in that: the mixing chamber has a longitudinal direction in the flowing direction of the air-conditioning air, and a width direction in a direction intersecting the flowing direction of the air-conditioning air, and a rectifying surface of the rectifying portion has a width over an entire area of the mixing chamber in the width direction or over part of the area of the mixing chamber in the width direction, wherein the rectifying surface of the rectifying portion has different length depending on portions in the width direction. a cold air flow channel in which cold air flows; a warm air flow channel in which warm air flows; a mixing chamber configured to mix the cold air and the warm air to create air-conditioning air; a cold air opening that opens between the cold air flow channel and the mixing chamber; a warm air opening that opens between the warm air flow channel and the mixing chamber; a first opening and a second opening that open the mixing chamber; a third opening that opens the mixing chamber configured to blow out the air-conditioning air from a position lower than the first opening and the second opening; a case including at least the cold air flow channel, the warm air flow channel, the mixing chamber, the cold air opening, the warm air opening, the first opening, the second opening, and the third opening; a mix door configured to adjust a ratio between an amount of the cold air flowing from the cold air opening into the mixing chamber and an amount of the warm air flowing from the warm air opening into the mixing chamber; air distribution doors (221, 231, 241) disposed in the mixing chamber or on the downstream thereof and configured to regulate a flow of the air-conditioning air from the mixing chamber to the first, second, and third openings; and a rectifying portion disposed in the vicinity of an upstream end of the mixing chamber and configured to rectify the warm air flowing from the warm air opening into the mixing chamber toward the third opening, characterized in that: the mixing chamber has a longitudinal direction in the flowing direction of the air-conditioning air, and a width direction in a direction intersecting the flowing direction of the air-conditioning air, and a rectifying surface of the rectifying portion has a width over an entire area of the mixing chamber in the width direction or over part of the area of the mixing chamber in the width direction, wherein the rectifying surface of the rectifying portion has different length depending on portions in the width direction. the mixing chamber has a longitudinal direction in the flowing direction of the air-conditioning air, and a width direction in a direction intersecting the flowing direction of the air-conditioning air, and a rectifying surface of the rectifying portion has a width over an entire area of the mixing chamber in the width direction or over part of the area of the mixing chamber in the width direction, wherein the rectifying surface of the rectifying portion has different length depending on portions in the width direction.