SERVO TRACK WRITER, SERVO INFORMATION WRITING METHOD BY SERVO TRACK WRITER

PROBLEM TO BE SOLVED: To reduce the price of a servo track writer, and to enhance the reliability by giving a floating guarantee function and improving the yield of a head disk assembly(HDA) in the servo track writer process of HDA process. SOLUTION: The servo track writer is provided with a floating guarantee circuit 8, and a MR element is used for a read-out reproduction element of a magnetic head 3 of a head disk assembly(HDA). The floating guarantee circuit 8 has a detecting circuit detecting a TA(thermal asperity) waveform caused by TA phenomenon of a head occurring at the time when a disk and a head come into contact, and a storage unit storing position information on a disk at the time of detecting a TA waveform. Prior to writing servo information, the servo track writer stores position information of a position at which contact by the floating guarantee circuit is performed, and it is prevented that servo information is written in the contact position at the time of writing servo information.