treasurer; person who holds the purse strings
Refers to the person in charge of the money or safe in an organization, often with a nuance of controlling the finances.
As the company's treasurer, he strictly manages expenses.
The club's treasurer is responsible for collecting and managing membership fees.
出納係 is a more formal term for a cashier or teller who handles receipts and disbursements, whereas 金庫番 has a slightly more informal, figurative nuance of 'money-keeper'.
Compound of 金庫 (safe, cash box) and 番 (watch, guard). Literally 'safe guard', referring to the person who watches over the money.