A method for the production of acrylic acid comprises a step for introducing a polymerization inhibitor to a stage other than a stage for supplying a raw material and a stage for supplying a reflux of said distilling column or a step for supplying the acrylic acid recovered by thermally decomposing said oligomer to said stage for dehydration. A mating face of the cover 160 and the lens 120 is slanted with respect to a direction in which the leg 180 extends. Some of the IO device adaptors have address translation caches for local storage of TCEs. A single device fits a great variety of containers and allows for a high degree of customization.