An inverter air-conditioner comprising: (a) a converter including: (a-1) an ac power supply; (a-2) a bridge rectifying circuit for full-wave rectifying an ac output from the ac power supply; (a-3) a smoothing capacitor to be coupled with a dc output terminal of the bridge rectifying circuit; (a-4) a reactor to be coupled between the ac power supply and a first end of an ac input to the bridge rectifying circuit; (a-5) zero-cross detecting means for detecting a zero point where an ac voltage of the ac power supply becomes 0 (zero); (a-6) bi-directional switch driving signal generating means for generating a signal for driving a bi-directional switch based on an output from the zero-cross detecting means; (a-7) bi-directional switch driving means for driving the bi-directional switch based on the signal supplied from the bi-directional switch driving signal generating means; (b) an inverter section for converting a dc output voltage from the converter into an ac voltage; (c) a compressor to be driven by the inverter section; and (d) speed control means which controls one of an output frequency and an output voltage from the inverter section so that the compressor can be driven at an instructed speed, wherein the converter further comprises a capacitor serially connected with the bi-directional switch, the serial connection of capacitor and bi-directional switch being connected between a second terminal of the ac power supply for the bridge rectifying circuit and one of a positive dc and a negative dc output terminal from the bridge rectifying circuit, wherein the bi-directional switch driving signal generating means generates an ON signal after a time lapse of Δd, 0 ≤ d, from a zero point where a voltage of the ac power supply becomes 0 (zero), and generates an OFF signal in Δt, 0 ≤ t, after generating the ON signal, for controlling both of harmonic component of an input current flowing in from the ac power supply and a dc output voltage across the smoothing capacitor, characterised in that the inverter air-conditioner further comprises an input current detecting means for detecting an input current; and memory means for storing in advance combinations of Δd and Δt responsive to the input current into the bi-directional switch driving signal generating means, wherein a combination of Δd and Δt is selected from the memory means responsive to the input current based on an output from the input current detecting means. (a) a converter including: (a-1) an ac power supply; (a-2) a bridge rectifying circuit for full-wave rectifying an ac output from the ac power supply; (a-3) a smoothing capacitor to be coupled with a dc output terminal of the bridge rectifying circuit; (a-4) a reactor to be coupled between the ac power supply and a first end of an ac input to the bridge rectifying circuit; (a-5) zero-cross detecting means for detecting a zero point where an ac voltage of the ac power supply becomes 0 (zero); (a-6) bi-directional switch driving signal generating means for generating a signal for driving a bi-directional switch based on an output from the zero-cross detecting means; (a-7) bi-directional switch driving means for driving the bi-directional switch based on the signal supplied from the bi-directional switch driving signal generating means; (a-1) an ac power supply; (a-2) a bridge rectifying circuit for full-wave rectifying an ac output from the ac power supply; (a-3) a smoothing capacitor to be coupled with a dc output terminal of the bridge rectifying circuit; (a-4) a reactor to be coupled between the ac power supply and a first end of an ac input to the bridge rectifying circuit; (a-5) zero-cross detecting means for detecting a zero point where an ac voltage of the ac power supply becomes 0 (zero); (a-6) bi-directional switch driving signal generating means for generating a signal for driving a bi-directional switch based on an output from the zero-cross detecting means; (a-7) bi-directional switch driving means for driving the bi-directional switch based on the signal supplied from the bi-directional switch driving signal generating means; (b) an inverter section for converting a dc output voltage from the converter into an ac voltage; (c) a compressor to be driven by the inverter section; and (d) speed control means which controls one of an output frequency and an output voltage from the inverter section so that the compressor can be driven at an instructed speed,