Abstract: A method of cramming electronic components into a plate-like casing, comprises preparing the casing having a spiral passageway, an opening as a continuation of the passageway to communicate with the exterior of the casing and vents; preparing components; sending the components to vibration-free zone while applying vibration to the components; feeding the foremost one of the components, forwarded to the vibration-free zone, into the passageway through the opening of the casing by the push of subsequent components against the foremost component; causing the foremost components to be moved toward an inside terminal portion of the spiral passageway, while applying vibration to the casing in a manner to cause the vibration, applied to the casing, to extend from an outside terminal portion of the spiral passageway to the inside terminal portion of the spiral passageway and permitting air in the passageway to escape through the vents; and feeding from the vibration-free zone and moving the subsequent components towa