According to the Article 227 of Commerce Law and Article 19 drawing cheque in respective with appointing a representation for issuance of draft and cheque, the following questions have always been present: a) whether this representation exists only at the time of signing a document or it will be present at other stages such as endorsement and assurance, too? b) Whether the responsibility of signing a document is always for the original person or under some conditions the representative will be considered responsible and obliged to pay? Although there isn’t a clear cut rule in Commerce Law appealing to other rules, particularly Commerce Law in commercial documents, Geneva and Uncitral conventions, and Law of some countries such as England and USA would lead to the following results: a) representation is not limited to the signing at the time of issuing the document but it includes the other subjects such as endorsement and assurance, b) the said representation is not only true for signing draft and cheque but also for signing the promissory note. c) the general rule in representation suggests that the original person is responsible, but under special conditions such as when the person who pretends to be the representative is not actually the representative or in case of being the real representative he has violated his powers or in spite of having enough power at the time of signing a document, he has not stipulated his representation and has not disclosed the identity of the original person.