A terminal holding structure of a flat circuit body includes: a flat circuit body having a plurality of conductors and insulating; a plurality of terminals provided on a terminal portion of the flat circuit body; and a connector housing having a plurality of terminal housing chambers for housing the plural terminals. In the above structure, the flat circuit body is formed with holding openings on portions on the terminal portion where the conductors are not located. Furthermore, the connector housing is detachably provided with a spacer which has engagement portions for engaging with the holding openings.