|Born:||March 31, 1970|
|Years active:||1989 - present|
|Spouse:||Unknown (currently married)|
He is Ultraman Belial's first voice actor. He voiced for this Ultra in Ultra Galaxy Legends The Movie and Ultraman Zero The Movie only. Currently, the role of Ultraman Belial is passed to voice actor Yuki Ono. Although no longer the voice in for Belial, his grunts were still kept and reused in some of Belial's later appearances.
- Hiroyuki Miyasako is married on 1998. His wife gave birth to their son in 2001.
- Hiroyuki used to be a smoker but when he was 37 years old (in 2007), he stopped and gave up smoking.
- On December 6, 2012, Hiroyuki announced that he will take a rest for early gastric cancer through his affiliated office. The cancer is a part called "stomach horn" and the size is about 2 cm. The stage is phase 1A. He underwent surgery for laparoscopic pyloric resection, removed two-thirds of the stomach, and were discharged on the 22nd of the same month. On December 29 of the same year, the year-end special program "Ame to ー ー ー ー ー ー ー ー ー ー ー 5! Hour Special" (broadcast on December 30 the same year) of "Yakka Rising Dying Corps Talk Show Ame Talk! TV program appearances. After that, full-scale job restoration from "Yamato Naze Shako after the rain" recorded on January 14, 2013. On April 5, 2014, in the TBS series broadcast "Morning of Sawako", Hiroyuki confessed that the doctor told him that Scirrhous stomach cancer was done after medical examination.