"I am really excited about the move", he told the clubs official website.
"It is a great opportunity to play some football and I am aiming to get some goals while I am here. I am impressed with what I have seen so far, and am taking everything one day at a time but obviously I am really looking forward to playing."
Harrad trained with the Millers this morning and is looking for his first goals of the season, having played 18 times for Bury, including 8 starts, without finding the net.
"I haven't really been able to get into the side at Bury so I took the opportunity to come here when it arose," he added. "I have met the lads and got on really well with them today, we have trained well and I have been impressed with what I've seen.
"I'll always give 100% no matter whether I score or not so if I can help the team climb the table, and move towards the play-offs then that would be great for all parties. "
Harrad, born in Nottingham, moved to Bury in the summer from Northampton after previously making his name at Burton Albion.
His 76 goals for the Brewers included a hat-trick at DVS last season in a 3-3 draw.