Is it possible to get it without using package
titletoc? I'm using special chapter style which doesn't work with this package.
There are so many options... without further information, one possible option would be to use the
This approach will increase evenly the space between all sectional units. The following three options allow you to control separately the spacing for each group of sectional units.
Another option would be to use the
Yet another option, this time using the
A fourth option not requiring any packages would be to redefine the
Using tocloft, you can also add the following in your preamble to add spacing before a section entry:
This complements Gonzalo's Answer in where he shows how to add spacing after a section entry: that can be undesirable in case you have subsections following a section. The tocloft's manual has many other options that can be used to manipulate other types of entries in the TOC.
While the other suggestions so far allow increasing the line spacing of the Table of Contents, it seems they don't allow decreasing it, for example to fit a ToC on one page.
will allow setting any line spacing.
It might be necessary to find out what your baselinestretch size is by default as the style seems to set this.