Hi Roz, and welcome.
This looks familiar somehow, but I can't place it. Have you posted it elsewhere on the internet?
My gut instinct is to say no, I'm afraid. From what I've seen, the shape is too curved for one thing, hooks had sharp points. Obviously it could have been worn down, but one can try to extrapolate the original shape from its pre-eroded state. I think the biggest stumbling block is the size, belemnite hooks were very small, maybe only a few millimetres long and this looks much larger. Don't forget that belemnites had two rows of these things on each arm and ten arms in total, scaling that up from the size of your fossil implies the belemnite would have been massive.
I assume you found this in the US? The largest belemnite was Megateuthis which is, as far as I know, unknown from the US and is mainly found in Europe and Indonesia. Also, hooks are very rarely preserved which makes the chances of you finding one very remote indeed I'm afraid.
Apologies for an unwelcome answer. Now we have to work out what it actually is of course!