The Czech midfielder has been a revelation for the Hammers this season as they push for a spot in Europe.
Manchester United have been linked with the 26-year-old, but Pearce has moved to quash those rumours.
Pearce told talkSPORT of Soucek: "No, he's happy here and he's not going anywhere, that's for sure.
"He's been brilliant here, I've got to say. Dave brought him into the club in January of last season and since then he's just been brilliant.
"He's got a wonderful attitude to work, on his days off he comes in to work, he's just really an absolute pleasure to work with.
"As a man he is top quality. He and [Vladimir] Coufal, the two Czech boys, they've both been brilliant.
"And Tomas can be a handful, too. England will face Czech Republic in the [Euro 2020] group stages and his ability in both boxes is very, very good."