I'm currently using a HB pencil to write notes for my schoolwork, but I realise that this particular pencil is very hard to erase. I tried using less pressure while writing, but it doesn't help. I'm using the Pentel eraser which worked fine on my 2B pencil but I changed to this HB pencil after losing it and it's hard to erase this one. However, this shouldn't be the case since a HB pencil is lighter than 2B, right? Is there any way to solve this problem?
Your pencil marks with the HB pencil are harder to remove because the pencil is harder and makes deeper marks in the paper and might even damage the top layer of the paper.
The easiest way is to replace your pencil with one as you used to use, a 2B pencil, or even one with a higher B number. The higher the B number, the softer the pencil, the stronger black the line but the faster your pencil will wear down.
There are many kinds of erasers, some will work better on some paper, others on other paper, and some will do better with some pencil marks and others with other pencil marks. I had the impression that soft gummy erasers did work better on my (HB) pencil lines, while the very soft blue kneadable gum did not work good enough. Harder erasers did tear more paper away, with the lines, but did get rid of most of the lines.
Your millage may vary, so try a few different ones on paper that is not important.
As also suggested in one of the comments, changing your paper may work. Some paper will take erasing pencil better than other, testing is the best way to find one that will work.
A way of last resort, for important items you have already made and which involved a lot of work and little correction needed, is the kind of white tape used to correct pen or typed/printed text. As it will likely stand out, you may need to make a photo copy of your page which will flatten our the differences in white of the paper.
I feel the same way. In art class at school, years ago, we had different types of pencils. I had always issues with using the HB because it was harder to erase. In reality, HB wasn't harder to erase, it just is lighter so I pushed harder on the paper. Pushing harder on the paper causes more 'damage', which makes erasing it more difficult. I would suggest that you try a better eraser, a stronger pencil, or a better eraser.
It's counterintuitive but I have found that how well you can erase pencil marks depends on the pencil hardness scale, with the middle levels being the best. The best erasing pencils I have are, as you noted, almost always 2B or thereabouts.
HB can be harder to erase because you are applying more pressure. You can fix this by moving to an F, B, or moving to another brand. You can also get a rougher eraser, that pulls up a little bit of paper in addition to removing the pencil marks.
I'd recommend another pencil brand though, as not all eraser equally well. Try something like the Mitsubishi 9800, which is excellent.