Which is the best engineering field with respect to securing a highly paid job?

One should choose the field more out of passion and not out of job security. There is a demand for all the fields. Yes some might be in more demand that others. But if one is interested and passionate about it, he/she will make a niche easier in the competitive world.

First choice of students is IT. But one must be choose field as per their interest.

It depends on demand and supply,  as of now Information science /technogy would be the one that leads, also mechanical..

By the way please dont ask the question in the title itself, not a good practice 

students should choose their filed as per as their interest.

In engineering Petroleum Engineers are most demanding and profitable field,