A fuel cell system for a vehicle includes a first cooling line configured to pass through a fuel cell stack in a vehicle and configured to circulate a first coolant therein, a first cooler provided in the first cooling line and configured to cool the first coolant, and a second cooler provided in the first cooling line and configured to cool the first coolant independently from the first cooler, thereby obtaining an advantageous effect of ensuring a high output from the fuel cell stack and improving safety and reliability.