…does not mean the same as ‘In contrast’!

‘On the contrary’ is used to:

• ADD to a negative statement
• disagree with a negative statement made by someone else
• answer NO to a question

e.g.

• ‘It wasn’t a good thing. On the contrary, it was a huge mistake’.
• ‘I suppose it’s very expensive.’ ‘On the contrary, it’s actually very reasonable’.
• ‘Is it expensive?’ ‘No, quite the contrary’.

Don’t use ‘On the contrary’ – it’s dangerous.

‘In/By contrast’ 

…is used to introduce the opposite point of view/situation.

This is the one you need in your IELTS Test.