Abstract: A folding knife comprising a handle and a knife blade rotatable about a pivot. The invention is characterized by the combination that the handle (2) consists of only one wood piece, which is sawn open along a central longitudinal plane, so that a longitudinal gap (5) is formed along the greater part, but not along the entire length of the handle (2), that the blade pivot is located at the end (7) of the handle (2) where the gap (5) opens and is attached in the wood portions of the handle (2) located on opposite sides of the gap, and that a retaining mechanism known per se capable to retain the knife blade (4) in folded-out position and in a spring-loaded manner to retain the knife blade in folded-in position is provided. The retaining mechanism comprises a retaining arm (12) and a spring (13) acting against the same, which are mounted in the longitudinal gap (5) and have a thickness corresponding to the width of the gap (5).