An air-conditioning apparatus for a railway vehicle, comprising: - a plurality of refrigerant circuits each including a compressor (1a, 1b), a first heat exchanger (3a, 3b), an expansion device (6a, 6b), and a second heat exchanger (4a, 4b) that are connected to each other by pipes; - an inverter connected to an auxiliary power supply device of a railway vehicle and configured to control a frequency of the compressor (1a, 1b); - a switching unit configured to switch between wiring connection for supplying power to the compressor (la, 1b) via the inverter and wiring connection for directly supplying power from the auxiliary power supply device to the compressor (la, 1b); - a controller (el) configured to control a switching operation of the switching unit in such a manner that, when an air conditioning load of a boarding space of the railway vehicle is higher than a load threshold value, wiring for directly supplying power from the auxiliary power supply device to at least one of the compressors (la, 1b) of the plurality of refrigerant circuits is established; - a plurality of indoor units each including the second heat exchanger (4a, 4b) and configured to blow out air subjected to heat exchange by the second heat exchanger (4a, 4b) and passing through a corresponding one of air outlet ducts to a corresponding one of different positions in the boarding space; and - a plurality of temperature sensors each provided at a corresponding one of different positions in the boarding space and each configured to measure a temperature of the corresponding one of the different positions in the boarding space, wherein the controller is configured to calculate a load distribution in the boarding space on a basis of the temperatures measured by the plurality of temperature sensors, and control the switching operation of the switching unit, on a basis of the load distribution, to either directly supply power from the auxiliary power supply device individually to a plurality of the compressors (1a, 1b) or supply power from the auxiliary power supply device via the inverter to the plurality of the compressors (1a, 1b). - a plurality of refrigerant circuits each including a compressor (1a, 1b), a first heat exchanger (3a, 3b), an expansion device (6a, 6b), and a second heat exchanger (4a, 4b) that are connected to each other by pipes; - an inverter connected to an auxiliary power supply device of a railway vehicle and configured to control a frequency of the compressor (1a, 1b); - a switching unit configured to switch between wiring connection for supplying power to the compressor (la, 1b) via the inverter and wiring connection for directly supplying power from the auxiliary power supply device to the compressor (la, 1b); - a controller (el) configured to control a switching operation of the switching unit in such a manner that, when an air conditioning load of a boarding space of the railway vehicle is higher than a load threshold value, wiring for directly supplying power from the auxiliary power supply device to at least one of the compressors (la, 1b) of the plurality of refrigerant circuits is established; - a plurality of indoor units each including the second heat exchanger (4a, 4b) and configured to blow out air subjected to heat exchange by the second heat exchanger (4a, 4b) and passing through a corresponding one of air outlet ducts to a corresponding one of different positions in the boarding space; and - a plurality of temperature sensors each provided at a corresponding one of different positions in the boarding space and each configured to measure a temperature of the corresponding one of the different positions in the boarding space,