これは鉛筆じゃありません

[Maybo]

Is this a pencil?
If I want to answer "this is not a pen", can I say "これは鉛筆じゃありません"？

 

[Toritoribe]

Yes. これは鉛筆じゃありません exactly means "this is not a pencil".

 

[SomeCallMeChris]

Is this a pencil?
If I want to answer "this is not a pen", can I say "これは鉛筆じゃありません"？

If you want to answer 'this is not a pen' it would be これはペンじゃありません ... the sentence you wrote as Toritoribesan correctly points out means "This is not a pencil".

Not sure if there was just a typo in the English, and it may not matter at this late date, but I thought it might be best to clarify.