An air-conditioning apparatus, comprising: at least two intermediate heat exchangers (15a, 15b) that are configured to exchange heat between a refrigerant under two-phase transition or under a supercritical condition and a heat medium such as water and an antifreezing liquid that is different from said refrigerant; a refrigeration cycle with which a compressor, an outdoor heat exchanger, at least one expansion valve, and a refrigerant side flow path of said intermediate heat exchangers (15a, 15b) are connected via piping through which said refrigerant flows; a heat medium circulation circuit with which a heat medium side flow path of said intermediate heat exchangers (15a, 15b), at least two pumps (21a, 21b), and a use side heat exchanger are connected via piping through which said heat medium flows; and a controller that is configured to control drive of said compressor and said pumps (21a, 21b), wherein said compressor and said outdoor heat exchanger are accommodated in a heat source device, said intermediate heat exchangers (15a, 15b) and said pumps (21a, 21b) are accommodated in a relay unit, and said use side heat exchanger is accommodated in an indoor unit, and said controller is configured to perform at least one of the following operations comprising_ a) the operation to stop one of said pumps (21a, 21b) that does not correspond to an operation mode after switching operation mode when performing switching from cooling-heating mixed operation mode that provides heating energy and cooling energy with said use side heat exchanger to heating only operation mode that provides only heating energy with said use side heat exchanger or cooling only operation mode that provides only cooling energy with said use side heat exchanger and b) the operation to perform switching said operation mode after starting one of said pumps (21a, 21b) that has been stopped before switching the operation mode when switching from heating only operation mode that provides only heating energy with said use side heat exchanger or cooling only operation mode that provides only cooling energy with said use side heat exchanger to cooling-heating mixed operation that provides heating energy and cooling energy with said use side heat exchanger. at least two intermediate heat exchangers (15a, 15b) that are configured to exchange heat between a refrigerant under two-phase transition or under a supercritical condition and a heat medium such as water and an antifreezing liquid that is different from said refrigerant; a refrigeration cycle with which a compressor, an outdoor heat exchanger, at least one expansion valve, and a refrigerant side flow path of said intermediate heat exchangers (15a, 15b) are connected via piping through which said refrigerant flows; a heat medium circulation circuit with which a heat medium side flow path of said intermediate heat exchangers (15a, 15b), at least two pumps (21a, 21b), and a use side heat exchanger are connected via piping through which said heat medium flows; and a controller that is configured to control drive of said compressor and said pumps (21a, 21b), wherein said compressor and said outdoor heat exchanger are accommodated in a heat source device, said intermediate heat exchangers (15a, 15b) and said pumps (21a, 21b) are accommodated in a relay unit, and said use side heat exchanger is accommodated in an indoor unit, and said controller is configured to perform at least one of the following operations comprising_ a) the operation to stop one of said pumps (21a, 21b) that does not correspond to an operation mode after switching operation mode when performing switching from cooling-heating mixed operation mode that provides heating energy and cooling energy with said use side heat exchanger to heating only operation mode that provides only heating energy with said use side heat exchanger or cooling only operation mode that provides only cooling energy with said use side heat exchanger and b) the operation to perform switching said operation mode after starting one of said pumps (21a, 21b) that has been stopped before switching the operation mode when switching from heating only operation mode that provides only heating energy with said use side heat exchanger or cooling only operation mode that provides only cooling energy with said use side heat exchanger to cooling-heating mixed operation that provides heating energy and cooling energy with said use side heat exchanger. a) the operation to stop one of said pumps (21a, 21b) that does not correspond to an operation mode after switching operation mode when performing switching from cooling-heating mixed operation mode that provides heating energy and cooling energy with said use side heat exchanger to heating only operation mode that provides only heating energy with said use side heat exchanger or cooling only operation mode that provides only cooling energy with said use side heat exchanger and b) the operation to perform switching said operation mode after starting one of said pumps (21a, 21b) that has been stopped before switching the operation mode when switching from heating only operation mode that provides only heating energy with said use side heat exchanger or cooling only operation mode that provides only cooling energy with said use side heat exchanger to cooling-heating mixed operation that provides heating energy and cooling energy with said use side heat exchanger.