A cassette for storing a plurality of electronic component chips employed for providing the plurality of electronic component chips to an apparatus for supplying electronic component chips comprises a plurality of electronic component chips; a case for storing the plurality of electronic component chips, which is provided with first and second outer wall surfaces adjacently intersecting with each other and an outlet formed in the first outer wall surface, the case also being for discharging the electronic component chips; and an openable closure for closing the outlet. The closure is formed by a flexible plate. The case has a guide portion for slidably guiding the closure over a portion along the first outer wall surface, and a portion along the second outer wall surface. The closure is guided by the guide portion to open and close the outlet, while one end portion thereof is positioned along the second outer wall surface whether the outlet is opened or closed. Such end portion of the closure is provided with a slidable opening/closing operation member, which is exposed on the second outer wall surface.