According to ITV, Shaps has not been pushed out, but decided "some time ago" that three years at the top of the programming department, where he has worked since 2005, were enough for him.
He is not leaving the company immediately and is staying on to hand over to Fincham, who is joining the company in May.Shaps' departure comes two months after a revamp of ITV1, with new dramas such as 'Moving Wallpaper', 'The Palace' and 'Honest' failing to deliver the hoped-for resurgence in its viewing figures.
In addition to the change in director of programmes, ITV has extended Michael Grade's contract by one year and promoted content head Dawn Airey and commercial head Rupert Howell to its executive board.
ITV's executive board previously consisted of just Grade and John Cresswell, who covered the two roles of chief operating officer and group finance director.
Cresswell is to give up the second role and ITV will recruit a new group finance director, who is expected to sit on the new five-strong executive board.
Fincham, who like Airey and Howell will report to Cresswell, will take direct control of ITV1, ITV2, ITV3 and ITV4.
Fincham was forced to resign from the BBC in October last year in the wake of "Queengate" -- the storm of controversy prompted by the claim at a preview of the documentary 'A Year with the Queen' that it showed Her Majesty storming out of a session with photographer Annie Leibovitz.
However, it materialised that the footage had been doctored by the production company RDF. A subsequent BBC investigation laid some blame at Fincham's door for his handling of the crisis after the world's media descended on the story.
Prior to joining the BBC in March 2005, Fincham was behind hit shows such as 'Pop Idol' and 'I'm Alan Partridge' as chief executive of Talkback Thames.
Grade, while saluting Fincham's experience, also praised Shaps' contribution to ITV and its regional forerunners LWT and Granada.
He said: "Simon told me some time ago that he wanted to do this job for a maximum of three years.
"He has made an inestimable contribution to ITV over 26 years... Simon bows out on a high, having delivered ITV's best year-on-year broadcast performance for many years."
Shaps said: "I would like to pay a special tribute to my commissioning, scheduling and commercial teams, who have delivered so much for our stakeholders -- audiences and advertisers alike."