JLPT N1Written, formalAdmonishing

たる・たるもの（は）one who is a … (must)

たる is an old である, so 教きょう師したる者もの is "anyone who is a teacher". It names a role in order to say what is expected of whoever holds it: an admonition in a lofty voice. The plain word is として.

医い師したるものは、患かん者じゃの尊そん厳げんを第だい一いちに考かんがえなければならない。

A doctor must put the patient's dignity first.

一いっ国こくの代だい表ひょうたる首しゅ相しょうは、言こと葉ばの重おもみを自じ覚かくすべきだ。

As the representative of a nation, a prime minister should be aware of the weight their words carry.

The usual frame

Role + たるもの（は）+ what is expected

Also written たる者もの. The は often gives way to a comma: 教きょう師したる者もの、….

Before a noun

Role + たる + noun

国こく民みんの代だい表ひょうたる議ぎ員いん: legislators, being the people's representatives. 〜たるにふさわしい is "fit to be a …".

Before it: A role with standards to live up to: 教きょう師し, 医い師し, 政せい治じ家か, 指し導どう者しゃ, 親おや, プロ.
After it: A duty or a ban: 〜なければならない, 〜べきだ, 〜てはならない.
Tone: Admonishing and lofty.
Where you'll meet it: Speeches, editorials, codes of conduct, a senior's lecture, period dramas (武ぶ士したる者もの). Seldom in ordinary conversation, except as a joke.

In use

教きょう師したる者もの、常つねに学まなび続つづけなければならない。

A teacher must never stop learning.

王おう者じゃたるものは、勝しょう利りに驕おごってはならない。

A champion must not let victory go to his head.

教きょう育いく機き関かんたる大だい学がくには、学がく問もんの自じ由ゆうを守まもる責せき務むがある。

A university, being a place of education, has a duty to protect academic freedom.

彼かれこそ会かい長ちょうたるにふさわしい人じん物ぶつだ。

He is the very person fit to be chairman.

About something small it is a joke

The grand voice needs a weighty role and a real duty. People borrow it for fun.

Sounds odd: 学がく生せいたるもの、毎まい日にちラーメンを食たべるべし。

A student shall eat ramen every day.

Mock-solemn.

Other たる

After a describing word, たる is an old adjective ending, and no duty follows: 堂どう々どうたる態たい度ど (a commanding manner), 微び々びたるもの (next to nothing), 最さいたるもの (the prime example).

Close neighbours

としてN3

The plain "as": it names the role someone acts in and lays down nothing. In plain words the duty is 教きょう師しとして、〜べきだ.

私わたしは研けん修しゅう生せいとして会かい議ぎに参さん加かした。

I attended the meeting as a trainee.

ともあろうN1

Dismay at a lapse: someone of that standing has done what they never should.

警けい察さつ官かんともあろう者ものが、飲いん酒しゅ運うん転てんをするとは信しんじられない。

A police officer, of all people, driving drunk: I can't believe it.

Check yourself

1Which sentence sounds natural?

Choose an answer to see why.

2Which one is meant as a joke?

Choose an answer to see why.

More sentences

指し導どう者しゃたるものは、判はん断だんの理り由ゆうを社しゃ会かいに説せつ明めいする責せき任にんがある。

Leaders have a responsibility to explain the reasons for their decisions to the public.

研けん究きゅう者しゃたるものは、自じ説せつに反はんする証しょう拠こも公こう正せいに検けん討とうすべきである。

A researcher should give fair consideration even to evidence that goes against their own theory.

国こく民みんの代だい表ひょうたる議ぎ員いんは、決けっ定ていの根こん拠きょを明あきらかにする責せき任にんを負おう。

Legislators, as the people's representatives, bear the responsibility of making clear the grounds for their decisions.

裁さい判ばん官かんたるものは、世せ論ろんに流ながされず法ほうに基もとづいて判はん断だんしなければならない。

A judge must decide according to the law, without being swayed by public opinion.