A vehicle air conditioner comprising: a cooling heat exchanger cooling air-conditioning air; a heating heat exchanger heating air-conditioning air; a casing including: a cold air passage provided with the cooling heat exchanger; a warm air passage communicating with a downstream portion of the cold air passage, and provided with the heating heat exchanger; a bypass passage branched from the downstream portion of the cold air passage and bypassing the warm air passage; an air mixing space allowing a downstream portion of the warm air passage to communicate with a downstream portion of the bypass passage; and a defrost outlet, a vent outlet, and a heat outlet each communicating with the air mixing space; and an air mix damper disposed inside the casing and adjusting an amount of warm air flowing into the air mixing space from the downstream portion of the warm air passage and an amount of cold air flowing into the air mixing space from the downstream portion of the bypass passage, wherein a baffle is disposed inside the casing at a position where the warm air and the cool air join together, and a central portion of the baffle in a vehicle widthwise direction is provided with a warm air guide tube guiding the warm air which has flowed through the warm air passage toward the defrost outlet, the baffle includes a left cold air guide tube on a left side of the warm air guide tube guiding the cold air which has flowed through the bypass passage toward at least one of the vent outlet or the heat outlet, characterized in that: the baffle includes a right cold air guide tube on a right side of warm air guide tube guiding the cold air which has flowed through the bypass passage toward at least one of the vent outlet or the heat outlet, the baffle is provided with a warm and cold air mixing passage (18, 19) mixing the warm air which has flowed through the warm air passage and the cold air which has flowed through the bypass passage together, the vent outlet is disposed below the defrost outlet, and the left cold air guide tube and the right cold air guide tube are disposed in a lower portion of the baffle. a cooling heat exchanger cooling air-conditioning air; a heating heat exchanger heating air-conditioning air; a casing including: a cold air passage provided with the cooling heat exchanger; a warm air passage communicating with a downstream portion of the cold air passage, and provided with the heating heat exchanger; a bypass passage branched from the downstream portion of the cold air passage and bypassing the warm air passage; an air mixing space allowing a downstream portion of the warm air passage to communicate with a downstream portion of the bypass passage; and a defrost outlet, a vent outlet, and a heat outlet each communicating with the air mixing space; and a cold air passage provided with the cooling heat exchanger; a warm air passage communicating with a downstream portion of the cold air passage, and provided with the heating heat exchanger; a bypass passage branched from the downstream portion of the cold air passage and bypassing the warm air passage; an air mixing space allowing a downstream portion of the warm air passage to communicate with a downstream portion of the bypass passage; and a defrost outlet, a vent outlet, and a heat outlet each communicating with the air mixing space; and an air mix damper disposed inside the casing and adjusting an amount of warm air flowing into the air mixing space from the downstream portion of the warm air passage and an amount of cold air flowing into the air mixing space from the downstream portion of the bypass passage, wherein a baffle is disposed inside the casing at a position where the warm air and the cool air join together, and a central portion of the baffle in a vehicle widthwise direction is provided with a warm air guide tube guiding the warm air which has flowed through the warm air passage toward the defrost outlet, the baffle includes a left cold air guide tube on a left side of the warm air guide tube guiding the cold air which has flowed through the bypass passage toward at least one of the vent outlet or the heat outlet, characterized in that: the baffle includes a right cold air guide tube on a right side of warm air guide tube guiding the cold air which has flowed through the bypass passage toward at least one of the vent outlet or the heat outlet, the baffle is provided with a warm and cold air mixing passage (18, 19) mixing the warm air which has flowed through the warm air passage and the cold air which has flowed through the bypass passage together, the vent outlet is disposed below the defrost outlet, and the left cold air guide tube and the right cold air guide tube are disposed in a lower portion of the baffle. the baffle includes a right cold air guide tube on a right side of warm air guide tube guiding the cold air which has flowed through the bypass passage toward at least one of the vent outlet or the heat outlet, the baffle is provided with a warm and cold air mixing passage (18, 19) mixing the warm air which has flowed through the warm air passage and the cold air which has flowed through the bypass passage together, the vent outlet is disposed below the defrost outlet, and the left cold air guide tube and the right cold air guide tube are disposed in a lower portion of the baffle.