There is provided a method for saving fault wave data, in which when a fault wave generated in a system is saved, a size of wave data is calculated, and the saving of the wave data is performed according to the size of the wave data, so that it is possible to implement the use of spaces of a buffer and a memory and the simultaneous saving of wave data simultaneously or subsequently generated. Accordingly, it is possible to minimize a delay in the saving of the wave data. Also, it is possible to record all accurate wave data even when consecutive faults occur. Also, it is possible to efficiently use the space of the memory.