An exposure apparatus has an optical system and transfers a pattern of a mask
to a substrate via the optical system. The apparatus includes a structure, a partition
wall which defines a space including an optical path of the optical system, and
an elastic seal member which couples the structure and the partition wall to seal
the space. The elastic seal member is arranged so that a hollow cylinder is compressed
in a direction of an axis of the hollow cylinder. The hollow cylinder, in an uncompressed
state, includes a member undulated in a cross section perpendicular to the axis
and a shape of the uncompressed-state hollow cylinder in the cross section being
substantially uniform along the axis.
