The £43,000 device allows Claire Lomas to walk by detecting shifts in her balance.
Mrs Lomas, from Eye Kettleby near Melton Mowbray, was paralysed from the chest down when she broke her back in a horse-riding accident in 2007.
The 32-year-old crossed the finish line at 12:50 BST – 16 days after starting the race with 36,000 other people.
She was met by cheering onlookers and a Pearly King and Queen as she walked beneath an arch of red balloons.
Mrs Lomas said: "It was really emotional and I couldn’t believe the support – I’m still in shock really.
‘Good group’
"The last half a mile or so was pretty easy to walk because I had everyone just pushing me forward," she said.
"I’ve had a really good group with me and it would have been impossible without them."
So far she has raised about £80,000 for Spinal Research, a charity which funds medical research around the world to develop treatments for paralysis caused by a broken back or neck.
Mrs Lomas walked about two miles a day to complete the course, accompanied by her husband Dan, mother Joyce and 13-month-old daughter Maisie.
Organisers have been criticised for insisting that Mrs Lomas would not appear in the official results or receive a medal for finishing, as rules state competitors must complete the course on the same day.
The 32-year-old broke her neck, back and ribs and punctured a lung when her horse threw her off as she took part in the Osberton Horse Trials in Nottinghamshire.