An air conditioning device for vehicle, the air conditioning device comprising: a first water-refrigerant heat exchanger that exchanges heat between a refrigerant of low-temperature and low-pressure and a coolant for heat transport to vaporize the refrigerant of low-temperature and low-pressure; a second water-refrigerant heat exchanger that exchanges heat between the refrigerant of high-temperature and high-pressure discharged from a compressor that compresses the refrigerant and the coolant to condense the refrigerant of high-temperature and high-pressure, and provides the heated coolant to a heater core that heats air to be sent into a vehicle interior; a first bypass passage (18b and 18a) that branches at a point of a coolant passage from a cooling portion of a heating component in the vehicle to the second water-refrigerant heat exchanger, the first bypass passage (18b and 18a) having a downstream end capable of being communicated with a point of the coolant passage at an upstream side of the first water-refrigerant heat exchanger; a second bypass passage (18c and 18a) that has an upstream end branching at a point of the coolant passage from the heater core to the first water-refrigerant heat exchanger, the second bypass passage (18c and 18a) being capable of being communicated with a point of the coolant passage at a downstream side of the first water-refrigerant heat exchanger; and a selector, wherein a part of the first bypass passage (18b and 18a) which includes the downstream end and a part of the second bypass passage (18c and 18a) which includes the upstream end are shared, characterized in that the part shared by the first bypass passage (18b and 18a) and the second bypass passage (18c and 18a) is defined as a shared passage, a part of the first bypass passage (18b and 18a) excluding the shared passage is defined as a first branch passage, and a part of the second bypass passage (18c and 18a) excluding the shared passage is defined as a second branch passage, and the selector is formed into one unit and switches to one of three communication states in which the first branch passage, the second branch passage, and the shared passage communicate, the three communication states being a state of blocking all of the passages, a state of allowing only communication between the first branch passage and the shared passage, and a state of allowing only communication between the second branch passage and the shared passage. a first water-refrigerant heat exchanger that exchanges heat between a refrigerant of low-temperature and low-pressure and a coolant for heat transport to vaporize the refrigerant of low-temperature and low-pressure; a second water-refrigerant heat exchanger that exchanges heat between the refrigerant of high-temperature and high-pressure discharged from a compressor that compresses the refrigerant and the coolant to condense the refrigerant of high-temperature and high-pressure, and provides the heated coolant to a heater core that heats air to be sent into a vehicle interior; a first bypass passage (18b and 18a) that branches at a point of a coolant passage from a cooling portion of a heating component in the vehicle to the second water-refrigerant heat exchanger, the first bypass passage (18b and 18a) having a downstream end capable of being communicated with a point of the coolant passage at an upstream side of the first water-refrigerant heat exchanger; a second bypass passage (18c and 18a) that has an upstream end branching at a point of the coolant passage from the heater core to the first water-refrigerant heat exchanger, the second bypass passage (18c and 18a) being capable of being communicated with a point of the coolant passage at a downstream side of the first water-refrigerant heat exchanger; and a selector, wherein a part of the first bypass passage (18b and 18a) which includes the downstream end and a part of the second bypass passage (18c and 18a) which includes the upstream end are shared, characterized in that the part shared by the first bypass passage (18b and 18a) and the second bypass passage (18c and 18a) is defined as a shared passage, a part of the first bypass passage (18b and 18a) excluding the shared passage is defined as a first branch passage, and a part of the second bypass passage (18c and 18a) excluding the shared passage is defined as a second branch passage, and the selector is formed into one unit and switches to one of three communication states in which the first branch passage, the second branch passage, and the shared passage communicate, the three communication states being a state of blocking all of the passages, a state of allowing only communication between the first branch passage and the shared passage, and a state of allowing only communication between the second branch passage and the shared passage.