hello,

circuit breaker is a piece of equipment with mechanism which can manually or by using remote control can detach the circuit under fault conditions.

where fuse is a short piece of metal, inserted in the circuit, which melts when excessive current flows on circuit hence detach the circuit from the connection of mains.

the main difference is fuse  melts when overheated, circuit breakers on the other hand, have internal switch mechanisms that can be tripped by an unsafe surge of electricity.