To provide an image input/output apparatus facilitating the attachment of a foreign-matter avoiding cover for preventing a foreign matter placed on a document cover from entering a sheet feed opening.

The image input/output apparatus comprises a housing having a table for mounting a document, a substantially planar foreign-matter avoiding cover having a shaft, a section for supporting the foreign-matter avoiding cover to oscillate between the oscillation axis of a document cover and a sheet feed opening comprising a bearing having a U-shaped recess, a resiliently deformable hook for stopping the shaft engaging with the recess, and a means for regulating further oscillation in the tilting direction when the foreign-matter avoiding cover oscillates at a specified angle in the tilting direction from a standing attitude to project obliquely upward from the housing, and a recess formed between the oscillation axis of the foreign-matter avoiding cover and the sheet feed opening and receiving a foreign matter lowering along the foreign-matter avoiding cover.