To provide a semiconductor integrated circuit that includes a flash EEPROM on which an efficient burn-in test can be carried out and a burn-in test method thereof. By changing the level of a control signal C1 from the mode selecting unit 40, the operating mode of a functional unit 10 is switched from a normal mode to a test mode for reading out data from a ROM 30 storing a test instruction code. Then, by changing the level of the first control signal C2 in the test mode, the destination of an output of the first selection circuit 12 and the operation of the program counter 11 are switched, thereby alternately implementing a first burn-in mode for activating a flash EEPROM 20 and a second burn-in mode for activating the functional unit 10.