PURPOSE: To save trouble of setting an optimum recording characteristic again when a magnetic tape for which its optimum recording characteristic is once set is used for recording.

CONSTITUTION: Before recording operation is performed, an optimum recording characteristic is set by an optimum recording characteristic setting block 10 in recording/reproducing a test signal outputted from a test signal generating block 14. Afterward, at the time of ordinary recording operation, an information signal corresponding to the optimum recording chatacteristic for this recording operation is recorded together with a main signal. When a magnetic tape recorded with the information signal is recorded again, the optimum recording characteristic is read out of a memory block 12 to optimize the recording characteristic of the tape. Thus, the information signal is recorded in a position not to interrupt the normal recording and reproducing of the main signal of the magnetic tape, and by reading out this signal at the time of recording again, the optimum recording characteristic can be set.