Every business has to make payments involving smaller or petty amount, e.g., carriage, cartage, coolly hire, postage telegrams etc. Such payments, by their very nature cannot be made by cheque. It is usual for the business units to maintain a separate cash book to record small payments only. Such cash book is known as Petty cash book. It relieves the main cash book of numerous transactions involving petty sums and also helps in reducing the work-load of chief cashier.