A saving box is disclosed, which senses an amount of a coin (1) in accordance with the size of the coin (1) thrown in the saving box and automatically releases a locking unit (40) in accordance with the sensed amount. To this end, an electrical contact node (24) is installed in a rotating lever (22), and a plurality of another contact nodes (24) are installed to electrically connect with the contact node (24) of the lever (22) in accordance with a rotational angle. Thus, the number of coins (1) thrown in the saving box can be checked by a simple mechanism. At the same time, the amount of the coins (1) can be sensed by load of the coins (1) after the coins (1) pass through the lever (22).