The title tells us the speaker is a salaryman, an office worker, and the poem sketches a life shrunk down to the job. The opening line has him "lock my use up in work," as if his usefulness is something valuable he has to hand over and keep under key. In return he gets to "own the top troubles," which suggests that the work gives him a kind of grim status: he holds the biggest worries, though they hardly seem like a prize.
The office becomes "an all-afternoon coop," a small pen like one for chickens. That image makes the workplace feel cramped, repetitive, and a little undignified. The last line is flat and quietly sad: "I count to go to bed." Even rest seems like something to be tallied and managed, as if sleep is just another task, or he is counting the hours until the day can end. The mood is weary, dry, and numb, with the speaker seeming resigned rather than angry.