A multi-room air conditioning apparatus comprising: a plurality of indoor units (5-1, 5-2, 5-n); a compressor; an outdoor heat exchanger; a four-way valve; a plurality of electronic expansion valves (4-1, 4-2, 4-n) corresponding to said plurality of indoor units (5-1, 5-2, 5-n), respectively; and a control device for controlling said compressor, said outdoor heat exchanger, said four-way valve, said plurality of indoor units (5-1, 5-2, 5-n), and said plurality of electronic expansion valves (4-1, 4-2, 4-n), characterized in that said control device is configured to perform the following processing steps of activating a refrigerating cycle when an opening degree of said electronic expansion valves (4-1, 4-2, 4-n) has not yet been initialized: (a) each opening degree of only electronic expansion valves (4-1, 4-2, 4-n) corresponding to all of said indoor units (5-1, 5-2, 5-n) which have issued an operation command is initialized; (b) after the initialization is completed for said electronic expansion valves (4-1, 4-2, 4-n) corresponding to all of said indoor units (5-1, 5-2, 5-n) which have issued an operation command, said compressor is activated; then (c) the opening degree of said electronic expansion valves (4-1, 4-2, 4-n) whose initialization has been completed is adjusted to a predetermined operational opening degree; and then (d) each opening degree of said electronic expansion valves (4-1, 4-2, 4-n) corresponding to said indoor units (5-1, 5-2, 5-n) which have issued no operation command is initialized and then is adjusted to a predetermined opening degree. a plurality of indoor units (5-1, 5-2, 5-n); a compressor; an outdoor heat exchanger; a four-way valve; a plurality of electronic expansion valves (4-1, 4-2, 4-n) corresponding to said plurality of indoor units (5-1, 5-2, 5-n), respectively; and a control device for controlling said compressor, said outdoor heat exchanger, said four-way valve, said plurality of indoor units (5-1, 5-2, 5-n), and said plurality of electronic expansion valves (4-1, 4-2, 4-n), characterized in that said control device is configured to perform the following processing steps of activating a refrigerating cycle when an opening degree of said electronic expansion valves (4-1, 4-2, 4-n) has not yet been initialized: (a) each opening degree of only electronic expansion valves (4-1, 4-2, 4-n) corresponding to all of said indoor units (5-1, 5-2, 5-n) which have issued an operation command is initialized; (b) after the initialization is completed for said electronic expansion valves (4-1, 4-2, 4-n) corresponding to all of said indoor units (5-1, 5-2, 5-n) which have issued an operation command, said compressor is activated; then (c) the opening degree of said electronic expansion valves (4-1, 4-2, 4-n) whose initialization has been completed is adjusted to a predetermined operational opening degree; and then (d) each opening degree of said electronic expansion valves (4-1, 4-2, 4-n) corresponding to said indoor units (5-1, 5-2, 5-n) which have issued no operation command is initialized and then is adjusted to a predetermined opening degree. (a) each opening degree of only electronic expansion valves (4-1, 4-2, 4-n) corresponding to all of said indoor units (5-1, 5-2, 5-n) which have issued an operation command is initialized; (b) after the initialization is completed for said electronic expansion valves (4-1, 4-2, 4-n) corresponding to all of said indoor units (5-1, 5-2, 5-n) which have issued an operation command, said compressor is activated; then (c) the opening degree of said electronic expansion valves (4-1, 4-2, 4-n) whose initialization has been completed is adjusted to a predetermined operational opening degree; and then (d) each opening degree of said electronic expansion valves (4-1, 4-2, 4-n) corresponding to said indoor units (5-1, 5-2, 5-n) which have issued no operation command is initialized and then is adjusted to a predetermined opening degree.