An air-conditioner for a vehicle, comprising: a vapor-compression refrigeration cycle that includes a compressor for compressing refrigerant, an inside condenser for exchanging heat between refrigerant compressed by the compressor and air to be supplied to a passenger compartment to heat the air, an outside heat exchanger (6,6A) for exchanging heat between refrigerant and air outside a passenger compartment, and an inside evaporator for exchanging heat between refrigerant and air to be supplied to a passenger compartment to cool the air, and is capable of operating an outside-air heat-absorption heating operation in which refrigerant absorbs heat at the outside heat exchanger (6, 6A)and refrigerant radiates heat at the inside condenser, and an inside-air heat-absorption heating operation in which refrigerant absorbs heat at the inside evaporator and refrigerant radiates heat at the inside condenser, characterized in that the air-conditioner further comprises: a determination unit for determining whether or not the outside heat exchanger (6, 6A) is frozen, and a controller that changes over the outside-air heat-absorption heating operation to the inside-air heat-absorption heating operation when the determination unit determines that the outside heat exchanger (6, 6A) is frozen, wherein the vapor-compression refrigeration cycle further includes a pressure regulator for regulating pressure of refrigerant to be supplied to the outside heat exchanger (6, 6A), a first bypass path bypassing the outside heat exchanger (6; 6A), a first flowpath changeover unit for changing over a refrigerant flow to the outside heat exchanger (6, 6A) or to the first bypass path, a pressure reducer for reducing pressure of refrigerant to be supplied to the inside evaporator, a second bypass path bypassing the inside evaporator, and a second flowpath changeover unit for changing over a refrigerant flow to the inside evaporator or to the second bypass path, wherein, in the outside-air heat-absorption heating operation, a refrigerant path is set, in which refrigerant compressed by the compressor flows sequentially through the inside condenser, the pressure regulator, the outside heat exchanger (6, 6A) and the second bypass path, and then returns to the compressor, wherein the pressure regulator decompresses refrigerant, and, wherein, in the inside-air heat-absorption heating operation, a refrigerant path is set, in which refrigerant compressed by the compressor flows sequentially through the inside condenser, the first bypass path, the pressure reducer and the inside evaporator, and then returns to the compressor, wherein the pressure reducer decompresses refrigerant. a vapor-compression refrigeration cycle that includes a compressor for compressing refrigerant, an inside condenser for exchanging heat between refrigerant compressed by the compressor and air to be supplied to a passenger compartment to heat the air, an outside heat exchanger (6,6A) for exchanging heat between refrigerant and air outside a passenger compartment, and an inside evaporator for exchanging heat between refrigerant and air to be supplied to a passenger compartment to cool the air, and is capable of operating an outside-air heat-absorption heating operation in which refrigerant absorbs heat at the outside heat exchanger (6, 6A)and refrigerant radiates heat at the inside condenser, and an inside-air heat-absorption heating operation in which refrigerant absorbs heat at the inside evaporator and refrigerant radiates heat at the inside condenser, a determination unit for determining whether or not the outside heat exchanger (6, 6A) is frozen, and a controller that changes over the outside-air heat-absorption heating operation to the inside-air heat-absorption heating operation when the determination unit determines that the outside heat exchanger (6, 6A) is frozen,