Eigyoubu no Takasugi-san wa Shinzou ni Warui

Tsutsumi works in an office as a clerk, but she's had a hard time working under the newest addition to their team with a mean streak for strict work ethics who came in from the sales department—Takasugi! However, it's not exactly the hard time anyone would have expected. After catching a moment of unexpected kindness from him, Tsutsumi can't do anything other than stiffen up and blush!!

(Source: MangaPlaza)