An assured-check computer-based bank credit disbursing system in which a bank-located unit or fixed unit transfers user-expendable credits to a portable unit for disbursement in check form by a user carrying the portable unit. A transfer code unique to each account of the portable unit must be entered in the fixed unit to activate it and the portable unit for the transfer. The user-expendable credits can be obtained from the bank in two ways on presentations of the portable unit to the bank by the user, namely, by cash payment to the bank and by loan from the bank; these are respectively designated as "cash" and "credit" when transferred by the fixed unit to the portable unit. The portable unit keeps in separate accounts the expendable balances of "cash" and "credit". The checks issued by the portable unit designate to which account each check is drawn as the checks are successively printed by the portable unit on proper manipulation of the portable unit keyboard by the user. Proper manipulation of the portable unit keyboard includes the entering by the user of a disbursement code unique to the individual user to activate the portable unit; regardless of manipulation, the portable unit will not issue a check overdrawing either account but will indicate the resultant negative balance. A tamper proof case is supplied to prevent fraudulent alteration of the portable unit accounts.