A saving box is disclosed, which senses an amount of a coin in accordance with the size of the coin thrown in the saving box and automatically releases a locking unit in accordance with the sensed amount. To this end, an electrical contact node is installed in a rotating lever, and a plurality of another contact nodes are installed to electrically connect with the contact node of the lever in accordance with a rotational angle. Thus, the number of coins thrown in the saving box can be checked by a simple mechanism. At the same time, the amount of the coins can be sensed by-load of the coins after the coins pass through the lever.