A redundancy circuit can include a first fuse set that is configured to
receive an address signal and an initializing signal activated when power
is up, and to output a first redundancy signal, the first redundancy
signal being used to repair a defective cell by using a laser beam
radiating method, a second fuse set that is configured to receive the
initializing signal, a specific address signal, a test mode signal that
is activated when a defective cell exists, and the address signal, and to
output a second redundancy signal, the second redundancy signal being
used to repair the defective cell by using an electrical fusing method, a
first memory cell array that is controlled by the first redundancy
signal, and a second memory cell array that is controlled by the second
redundancy signal.