A toner supply container detachably mountable to an image forming apparatus,
includes
a main body, provided with an opening for permitting discharge of the toner, for
accommodating the toner; a sealing member for unsealebly sealing the opening; wherein
the opening is unsealed by tearing a part of the sealing member, wherein a pattern
of welding with which the sealing member is welded on the main body of the container
is inclined inwardly with respect to a tearing direction at a laterally outward
end portion at a tearing starting side end portion.
