Assahola
you'll need a Allen wrench to remove that bolt
thebax2006
Looks like a 1/8" allen wrench is what you need. If you're in Japan or some where that uses metric tools try a 5 or 6 mm allen wrench.
boy boy
they are allen keys ..at least a 10mm probably 12mm
Anonymous
This type of tool, I don't know the name their hexagon shaped
Anonymous
It looks like you need an Allen (hex) key, 4 or 5mm would be my guess. Any hardware store will sell you a set.
One of your neighbours may have some they can lend you, most people's toolbox will have a set.