To provide an electronic toll collection system allowing an increase of the available balance without a user performing troublesome operation.

Based on information supplied from an on-vehicle apparatus through a road side apparatus, the available balance of an owner of an IC card inserted in the on-vehicle apparatus is confirmed (S41), and a toll is determined based on information supplied from the on-vehicle apparatus (S42). The available balance and the toll are compared, and if the balance is insufficient (No in S43) and if the user desires automatic increase beforehand (Yes in S45), the available balance is automatically increased (S48), and then the toll is settled (S50). In this manner, there is no need to increase the available balance by performing troublesome operation by the user. As a result, the electronic toll collection system is easy to use, and the use promotion of the electronic toll collection system can be expected.