The term investment deposits are one of the important modes of mobilization of resources in the Iranian banking system that are eligible for a certain provisional profit. According to the bank’s agency in this term of deposits, the appliance of Provisional Profit and its periodic payment to depositors before calculating of actual profit at the end of the fiscal year, are for incentives of customer’s improvement. Regardless of these advantages, there are some questions about Provisional Profit. One of the most important questions is that "can bank guarantee Provisional Profit for depositors in investment deposits?". By using the descriptive-analytical methodology and jurisprudential survey of agreeing and opposite views, this paper shows the current provisional profit assurance via bank encounter with some obstacles, but there are some legitimate solutions. According to the Plan of I.R. Iran Banking, this research offers a corrective suggestion for the plan finally.