PURPOSE:To complete the data base roll-back processing in a short period by using a main memory area where a user program for transaction processing is executed after resetting said memory area as a large-scale buffer which reads a number of blocks of an updating information storing file. CONSTITUTION:The blocks including the head block 1 through the block 100 are read into the 1st buffer 3a from an updating information storing file 2d for restoration of a data base. When this reading operation is through, the updating information on the blocks 1-100 are used successively for execution of the roll-back processing of the data base. At the same time, the next 100 blocks are read into the 2nd buffer 3b. When the roll-back processing is through with the first 100 blocks, the next 100 blocks of the buffer 3b are used for execution of the roll-back processing. Meanwhile other following 100 blocks are read into the buffer 3a with which the processing is through from the file 2d by a request. This action is repeated to carry out the roll-back processing at a high speed.