deputy manager; acting section chief
A corporate title for someone who acts on behalf of or assists a 課長 (section chief/manager). The exact English equivalent depends on the company's hierarchy.
He attended the meeting as the deputy section chief.
Mr. Tanaka, the acting manager, will explain.
課長 is the section chief or manager; 課長代理 is a deputy or acting role below 課長.
部長代理 is a deputy department head, one level above 課長代理 in a typical hierarchy.
Compound of 課長 (section chief) and 代理 (deputy, acting).