There has been constant speculation that the Dutchman will not fulfil his contract, which expires in 2017, because of United's poor season so far.
It has been widely reported that former Chelsea boss Jose Mourinho is waiting in the wings to take over, but Van Gaal seems to be taking the rumours lightly.
After witnessing his side seal a comfortable 3-0 victory over League One Shrewsbury Town in the fifth round of the FA Cup, Van Gaal signed some autographs for supporters.
One fan said, "All the best for the rest of the season, mate," and the 64-year-old replied: "Yeah, we need it. Otherwise, I shall be sacked."
United have lost 11 games in all competitions this season.