the invention provides a technique and a product in which for a frequency converter supplying electric power to , for example , a motor , a downsizing , lightening or the like of the frequency converter is realized while providing a filter apparatus reducing electromagnetic noises and the like . the filter apparatus reducing electromagnetic noises and the like is provided near a main circuit terminal board of the frequency converter , and the filter apparatus is connected directly to a main circuit terminal as a wiring drawing portion of the frequency converter . part of a housing of the frequency converter and part of a filter housing are fitted to each other to fix the filter housing to the frequency converter .