kikan no tantousya ni renrakusita.

The sentence breaks down like this:

• 機関 = organization / institution / agency
• の = links two nouns, similar to of or a possessive
• 担当者 = person in charge / representative / staff member responsible
• に = marks the target of contact
• 連絡した = contacted / got in touch

So the structure is:

[organization] の [person in charge] に [contacted]

In natural English, this is something like (I) contacted the person in charge at the organization.

Here, の connects 機関 and 担当者.

So:

• 機関の担当者 = the organization’s person in charge
• more naturally: the person in charge at the organization

This use of の is very common in Japanese. It often works like:

• possession: Tanaka’s book
• belonging: the school teacher
• category/relationship: Japanese culture, company employee, etc.

In this sentence, の shows that the 担当者 belongs to or is associated with the 機関.

に is used because 連絡する typically takes the person or place you contact with に.

So:

• 担当者に連絡した = contacted the person in charge

You can think of に here as marking the recipient/target of the contact.

This is different from English, where we often use contact directly without a preposition. In Japanese, the particle is required.

Japanese often leaves out the subject when it is obvious from context.

So 機関の担当者に連絡した does not explicitly say who did it. Depending on context, it could mean:

• I contacted...
• We contacted...
• He/She contacted...

In real Japanese, this is completely normal. If the speaker and situation are already clear, saying the subject would often sound unnecessary.

連絡した is the plain past form of 連絡する.

• dictionary form: 連絡する = to contact
• past plain form: 連絡した = contacted / got in touch

It shows that the action happened in the past.

Depending on context, it could mean:

• contacted
• got in touch
• reached out

Both are possible, but 連絡した is more compact and very common.

This is because 連絡する is a suru-verb:

• 連絡する = to contact
• 勉強する = to study
• 運動する = to exercise

Sometimes you will also see the noun + をする pattern:

• 連絡をした

That is grammatically fine, but 連絡した is usually more natural and more direct in a simple sentence like this.

Not exactly.

機関 usually refers to an institution, organization, agency, or some kind of formal body. It often sounds more official or institutional than 会社.

For example, 機関 might be used for:

• government bodies
• research institutions
• administrative organizations
• public agencies

会社 specifically means company or business firm.

So if the original sentence uses 機関, it suggests a more formal or institutional organization, not just any company.

担当者 means the person in charge, the responsible staff member, or the representative handling something.

It comes from:

• 担当 = being in charge of something
• 者 = person

So 担当者 is the person responsible for a task, case, customer, department, or situation.

Depending on context, it might be translated as:

• person in charge
• representative
• contact person
• staff member responsible

連絡した is plain form, so by itself it is not polite speech.

That means it sounds like:

• casual narration
• plain written style
• informal speech
• neutral reporting inside a conversation

A more polite version would be:

• 機関の担当者に連絡しました。

So the grammar is not rude, but it is less polite than しました.

Grammatically, 担当者 by itself does not clearly show singular or plural. Japanese often leaves number unspecified unless it matters.

So depending on context, it could refer to:

• the person in charge
• the staff member in charge
• sometimes even the people in charge

However, in many cases, readers will naturally understand it as a single representative unless the context suggests multiple people.

With 連絡する, に is the normal particle for the target of contact.

• 担当者に連絡した = contacted the person in charge

Using と would usually not be natural in this sentence.

That is because と often implies doing something with someone or marks a mutual relationship, while 連絡する normally focuses on the person you directed the contact to.

So for this verb, に is the expected choice.