Not sure on yours. Most have a set screw or two in the belly of the belt groove or a square head grub screw on the side of the pulley through to the shaft - in both cases often pushing on a key on the shaft.
Looking at your photo I see what I think is a hole for a drive pin. Is there another one 180 from that? If so, they Hub is prolly threaded on and can be turned off with a spanner wrench - but you might need to make a tool for that. Same applies to what looks like side lock grooves.
Edit - Cuslog noticed the same thing. Are there any threads on the shaft? Are they right or left handed?
I'm not sure I'm missing something in the photo but it looks to me like the pulley is retained by what I'd call a ring nut. The ring with the four notches and a fifth hole in its face. I can't tell but perhaps the fifth hole might have a set screw to lock it in place. I've also seen similar nuts locked by a metal washer with a tab which you bend up into one of the notches. That was on a 3/4 ton floating hub. My First mill table leadscrew adjusters have the same kind of ring nut.