Help! Potential New Prius Owner Looking at Car with Bad Fuse No Start?

Hello, I am looking at a 2005 Prius with 227k miles on it, I drove the car and it ran good and worked good, the owner says the big long fuse (about 5 inches long) on the left hand side of the fuse box needs to be replaced- and that occasionally the car will not start, when this happens he pushes the fuse together with a screw driver and it starts right up..

I don't know what this fuse is or if it is a serious issue.. Can anyone tell me if that could be a serious issue? the car does not have a check engine light or an exclamation mark on the dash board- everything works good and shows ready etc.

Any help is surely appreciated! Thanks
Tim