An operation method of an MRAM of the present invention is an operation method of the MRAM in which a data write operation is carried out in a toggle write. The operation method of the present invention includes: (A) reading a data from a data cell by using a reference signal which is generated by using a reference cell; (B) performing an error detection on the read data; (C) correcting the data stored in the data cell, when an error is detected in the read data; (D) reading the data from the data cell as a first re-read data after the (C), when the error is detected in the read data, (E) performing the error detection on the first re-read data; (F) correcting the data stored in the reference cell, when an error is detected in the first re-read data; (G) reading the data from the data cell as a second re-read data after the (F), when the error is detected in the first re-read data; (H) performing the error detection on the second re-read data; and (I) correcting the data stored in the data cell again, when the error is detected in the second re-read data.