The English FA brought the charge retrospectively after reviewing footage of Everton's 1-1 draw with Stoke on Saturday.
Fellaini and Everton accepted the ban, little surprise considering the player had already apologised and his manager David Moyes also condemned the incident, meaning he will miss the Toffees' next three games.
The ban is the equivalent of what the 25-year-old would have received had referee Mark Halsey seen the incident at the Britannia Stadium and issued a red card.
Fellaini will now miss Everton's Christmas fixtures against West Ham, Wigan and Chelsea and will not be available again until the trip to Newcastle on January 2.
A statement from the FA also referred to two other clashes between Fellaini and Shawcross at the Britannia Stadium but Halsey has confirmed he saw both and did not consider them violent conduct.
Fellaini's absence will be sorely felt by Everton after an inspirational first half of the season.
The Belgium international has scored eight goals and been the driving force of a team currently fifth in the table and pushing for a Champions League place.
A report on Everton's website confirmed that the Merseyside club would accept the charge.
Fellaini issued a statement after the game apologising for his actions. He said: "I apologise completely to Ryan Shawcross, my team-mates and to our fans at the game.
"There was a lot of pushing and pulling going on inside the Stoke penalty area and I didn't feel I was getting any protection from the officials.
"Nevertheless I know I shouldn't have done what I did.
"I have also apologised to the manager and the staff. I have no excuses."
Gordon Taylor, chief executive of the PFA, gave credit to Fellaini for his apology and to Moyes, who said he expected punishment.
Taylor said: "It is good to see the lad has apologised. It is disappointing, he has had a great season.
"It was refreshing to hear the manager accept what he did was wrong and for the player to apologise."