Dai-Guard is a tV series anime that premiered in fall 1999, produced by Xebec.

About the production: the story comes from an original script, there are 26 episodes of about 25 minutes and its current status is "finished".

Its main genres are adventure, comedy, mecha and sci-fi, with themes such as Work and Real Robot.

On AniList, Dai-Guard has an average score of 69%, a good score, and appears on 3,609 users' lists.

Thirteen years after their sudden disappearance, an alien race known as the Heterodyne resurface without warning. To combat the Heterodyne, three office workers from the 21st Century Security Corporation operate Dai-Guard - a giant robot no longer regarded as an oversized paperweight. Unfortunately, Dai-Guard is somewhat obsolete and in disrepair. It's a tough job, but salarymen can also save the world. (Source: Anime News Network)

Official synopsis from AniList.