🔎 失敗しない仕事選び
10 Warning Signs of a "Black Company"
Spotting red flags in job listings and interviews
📖 6分で読める📅 2026-04-25
"Wait — I haven't received any overtime pay at all!?"
That was the message Minh (26) from Vietnam sent to a friend back home the night he saw his first payslip. He had joined a food processing company in Tokyo in July 2023.
The job listing said: "A warm, family-like workplace" and "We value drive! A place where you can grow." On his first day, a senior employee told him, "This company is like a family. Overtime is just us helping each other out." Minh smiled and nodded.
He only understood what those words really meant when he saw the following month's payslip. There was a single line: "Deemed overtime: 45 hours included." No additional payment. His actual overtime was over 80 hours a month.
Four months later, Minh collapsed at work. He later said that taking paid leave "felt impossible in that atmosphere." His purpose in coming to Japan, and his goal of sending money home to his family — all of it crumbled in four months.
This workplace had shown 10 warning signs from the very beginning. If Minh had spotted them while reading the job listing, it could have been prevented.
If you're looking for work — make sure to check the list below.
01.The listing is full of phrases like "family-like" and "passion-driven"
These are buzzwords companies use when they can't speak in numbers or concrete policies. Try asking: "What is the average monthly overtime in hours?" If they can't answer with a number, that's a red flag.
02.The salary includes "deemed overtime (X hours included)"
Watch out for deemed overtime over 45 hours. Always ask: "What is the base salary?" and "Is overtime paid separately on top of that?"
03.When asked about overtime, they give vague answers like "it varies" or "it depends"
An honest company answers with a number: "About X hours per month on average." A company that can't answer either doesn't track it — or is hiding it.
04.The trial period exceeds 3 months with significantly lower pay
The standard maximum for a trial period is 3 months. If they keep wages low beyond that, be cautious. Always confirm whether social insurance enrollment applies during the trial period.
05.The job posting is always live (they recruit year-round)
This is a sign that people leave quickly. You may be able to check the company's posting history on Indeed or Kyujin Box.
06.After the offer, you're told "start next week — no contract needed"
You have the right to receive your employment contract before joining. Starting on a verbal promise means you have no evidence if they later say "we never said that."
07.You're told "paid leave starts after 1 year"
By law, 10 days of paid leave are granted after 6 months. "After 1 year" is illegal. Companies that make it "hard to take" paid leave are also a red flag.
08.The team is extremely young (almost no one over 30)
A workplace with no long-tenured employees is a sign that no one can stay long. If possible, try to speak with someone over 30.
09.You're told "we'll figure out your visa situation after you join"
Visa preparation should start as soon as hiring is confirmed. A company that keeps saying "later" is likely to be uncooperative when your visa renewal comes up.
10.OpenWork / Glassdoor / Indeed reviews show ★2 or lower across multiple sites
One site could be biased, but if multiple sites show the same rating, it's credible. Search for keywords like "overtime," "salary," and "harassment."
Minh later registered with GloJob and changed jobs. He now works at a place that properly pays overtime and lets him take paid leave. Companies listed on GloJob have passed compliance checks. Companies that hide behind phrases like "family-like workplace" cannot be listed.