A waste toner collecting container which is used in a color image forming apparatus and can be removed from the machine and stores waste toner particles which have not been transferred to recording paper and have been collected, is constructed such that an air sealing member is disposed at the coupling between the waste toner collecting container and a conveying member for conveying the collected waste toner into the waste toner collecting container to prevent the waste toner from seeping out at the coupling when the waste toner is conveyed and to seal the collecting port so that no waste toner will spill out from the waste toner collecting container which has been removed for replacement after the waste toner collected and conveyed therein has reached the predetermined amount.