houmonyoteizikan wo kime sidai, renrakusimasu.

It is read:

訪問予定時間を決め次第、連絡します。
ほうもんよていじかん を きめしだい、れんらくします。

In normal Japanese writing, it would usually appear without spaces: 訪問予定時間を決め次第、連絡します。

It is a compound noun made of:

• 訪問 = visit
• 予定 = plan / schedule
• 時間 = time

So 訪問予定時間 means something like the scheduled time for the visit or the appointment time for the visit.

Japanese often stacks nouns together like this, so you do not need extra particles inside the compound.

Because 決める is a transitive verb, meaning it acts on something.

Here, the thing being decided is 訪問予定時間, so it takes を:

訪問予定時間を決める = to decide the visit time

So を marks 訪問予定時間 as the direct object of 決める.

This sentence uses the grammar pattern:

verb stem + 次第

The verb 決める has the stem 決め, so:

• 決める → dictionary form
• 決め → stem
• 決め次第 → as soon as [someone] decides

So this is not a random shortening. It is a fixed grammar pattern.

Here, 次第 means as soon as or once.

So 決め次第、連絡します means: Once we decide it, we will contact you or As soon as it is decided, we will contact you.

This pattern is common in formal or business Japanese. It often suggests that the second action will happen promptly after the first one.

Yes.

• 決めたら、連絡します is understandable and more conversational.
• 決め次第、連絡します sounds more formal, business-like, and a little more set or procedural.

So in emails, customer service, or workplace Japanese, 次第 is very common.

Yes, absolutely.

There is a small difference:

• 訪問予定時間を決め次第 = once we decide the visit time
• 訪問予定時間が決まり次第 = once the visit time is set / decided

The first uses 決める and focuses on the person doing the deciding.
The second uses 決まる and focuses on the time becoming fixed.

In business Japanese, 決まり次第 is often very natural because it sounds a bit more neutral.

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

So this sentence does not explicitly say who is deciding. Depending on the situation, it could mean:

• I
• we
• our company
• the person in charge

This kind of omission is extremely common in Japanese and is one of the biggest differences from English.

Yes.

It is polite because it ends in 連絡します, which is ます-form.
It also sounds formal because of 次第.

A more formal business version might be:

• ご連絡します
• ご連絡いたします (more humble)

So the given sentence is polite and appropriate in many business contexts.

No. 次第 has more than one use.

For example:

• verb stem + 次第 = as soon as / once
• noun + 次第 = depending on / according to

So in this sentence, 決め次第 means as soon as [we] decide because 次第 comes after a verb stem.

That is different from something like:

天気次第です = It depends on the weather

It is not strictly required, but it is very common and natural.

The comma helps show the boundary between the two parts:

訪問予定時間を決め次第、連絡します。

It makes the sentence easier to read, especially in formal writing.

連絡します is a general expression meaning I will contact you.

It does not specify the method, so it can include:

• phone
• email
• message
• other forms of communication

That makes it very useful in formal Japanese, where the exact method may not matter or may already be understood from context.