Inverter with incorporated filter circuit and improved component cooling arrangement

An inverter includes a rectifier circuit (12), an inverter circuit (15), a filter circuit (19) including an input side capacitor (24), a coil (25a; 25b; 25c), and an output side capacitor (26), the filter circuit (19) being disposed at a front stage of the rectifier circuit (12), a casing (36) accommodating the inverter circuit (15), the rectifier circuit (12) and the filter circuit (19), a first cooling chamber (65) defined in the casing (36), a second cooling chamber (66) defined in the casing (36) and partitioned by a partition wall (64) from the first cooling chamber (65) so as to be adjacent to it, a plurality of vent holes (67, 68) formed in the partition wall (64), and a fan (39) for supplying a cooling air into the first cooling chamber (65) and further via the vent holes (67, 68) into the second cooling chamber (66). The inverter circuit (15) is cooled by the cooling air flowing into the first cooling chamber (65) and the coil (25a; 25b; 25c) of the filter circuit (19) is cooled by the cooling air flowing through the second cooling chamber (66).