The burglar can be seen attempting to use a National Lottery stand to break the glass and steal cash from the register.
Failing, the man removes panels from the ceiling to break in, to get behind the desk.
The Greater Manchester police released the video with hopes of catching the man.
The incident occurred on Christmas Eve, at around 11am, at the the Watchcote Post Office in Failsworth.
Detective Constable Tony Anwas said: "This CCTV paints perfectly the picture of just how desperate this man was to get his hands on some cash.
"I believe he has made a spur of the moment decision to rob the Post Office, and has executed his plan in a rushed and ham-fisted manner.
"We believe he was pacing about beforehand and making several comments about his dire financial position and inability to afford Christmas gifts."