Banks scored his fourth goal in three games before Armand Gnanduillet secured the points with a header on the stroke of half time.
Wycombe defended well up until the 31st minute when Jay O'Shea crossed from the right and Banks timed his run well to head in from six yards.
The visitors conceded again in first-half stoppage time when Gnanduillet rose to head a Gary Roberts corner past Matt Ingram but it needed a smart save from Tommy Lee on his 200th League appearance for Chesterfield to deny Billy Knott in the 49th minute.
Wycombe were starting to cause problems and former Chesterfield striker Dean Morgan went close with a low shot from the edge of the area in the 67th minute before Gary Doherty headed wide from a corner three minutes later.
They kept going right to the end but could not break down a solid Chesterfield defence which celebrated a fourth consecutive clean sheet in all competitions.
- Sports & Recreation
- Armand Gnanduillet