The Japanese translation from Korean of Bong-man Choi’s title as 常総務部長((Senior) Director of General Affairs is literally correct, but biographically it is a riddle.
You can find the full biography of Bong-man Choi on “North Korean Region Infonet” (www.cybernk.net), which is run by the Institute for Peace Affairs (https://www.ipa.re.kr/): (http://www.cybernk.net/infoText/InfoHumanDetail.aspx?mc=EJ09... His curriculum vitae lists nine titles, none of which correspond to a position in the General Affairs Department. And looking through the history of specialist departments in the North Korean government, you notice that the General Affairs Department has always been a separate department.
The interesting fact is that Bong-man Choi is famous for having been the director of Office No. 39, which managed the slush fund for Kim Jong-il and Kim Jong-un. This is why in his memoir Kim Jong Il's Chef, Kenji Fujimoto describes Bong-man Choi as an ex-Director of the Accounting Department. To be precise, he was the ex-Director of Office No. 39, which collaborated with both the General Affairs Department and the Finance & Accounting Department; and the last has also always been a separate department.

To answer your request for relevant resources, here are some that you might find useful:
1. North Korea’s ORGANIZATION AND GUIDANCE DEPARTMENT published by the Committee for Human Rights in North Korea (https://www.hrnk.org/uploads/pdfs/Collins_OGD_Web.pdf)

2. Freelance lawyer-interpreter James Yim Victory provides links in his website that show the organization chart of the Workers’ Party of Korea (https://www.nkleadershipwatch.org/the-party/) as well as the biographies of high ranking officers with their titles (https://www.nkleadershipwatch.org/leadership-biographies/)
He also provides a Korean>English glossary of office titles (http://www.koreandepos.com/485720), but you will need the Korean source text from which the Japanese text was translated where the comparison isn’t obvious.

Using his glossary, and taking into consideration the fact that “常” means permanent or senior, the Japanese to English translations are as follows:
常総務部長 Senior Director of General Affairs (Department)
常書記 Senior Secretary
常第第一副部長 Senior Deputy Director

3. You can find the names of North Korea’s government departments, ministries, bureaus, etc. in the “Governmental Organizations Glossary,” provided by the North Korean Information Portal of South Korea’s Ministry of Unification https://nkinfo.unikorea.go.kr/nkp/term/insttGrpFcltyEng.do).

4. In the “Parliamentary Diplomacy English Glossary” provided by South Korea’s International Affairs & Protocol Bureau, you can find two North Korean titles:
Chairman of Congress => Chairman of the Supreme People’s Assembly
Member of Congress => Delegate/Deputy
(https://www.assembly.go.kr/portal/prevew/docsPreview/preview...