Patent ID: 7823730

Claim:
A substrate storage container including: a container body of a front-opening box for storing substrates therein; a door for opening and closing the front of the container body; an attachment hole formed in at least one of the container body and the door; and an inner-pressure adjustment device attached to the attachment hole for adjusting the pressure inside the container body closed with the door, wherein the inner-pressure adjustment device comprises an elastic attachment cylinder removably fitted to the attachment hole by elastic deformation thereof without the use of an O-ring and formed in cylindrical shape having a first opening at one end face and a second opening smaller than the first opening at an other end face, a hollow filter support structure fitted into the attachment cylinder without any gap in the axial direction of the attachment cylinder from the first opening and a filter held inside the filter support structure, wherein the attachment cylinder has a pair of juxtaposed flanges integrally formed on the outer periphery thereof and fitted and engaged to the periphery of the attachment hole, and wherein the filter support structure is composed of a pair of support pieces arranged opposite to and attached to each other, each of said pair of support pieces having an approximately T-shaped or funnel-shaped section and at least one of the support pieces is tightly fitted from one side of the second opening of attachment cylinder toward an other side thereof so that a portion of the at least one of the support pieces projects out from the other side.