Abstract: In a method for mechanically removing intermuscular bones, so-called pin bones, from fillet parts of conveyed fish abdominal flaps for each fish are separated using a continuous, curved double separating cut. Each abdominal flap is simultaneously separated into two parallelly cut, completely free-moving parts having fish skin, which are conveyed away separate front one another. The first part is obtained as a narrow, curved pinbone strip, with a width corresponding to the row of pinbones and limited thereto. The second part is obtained as an abdominal flap meat body determined by the largest part of the separated abdominal flap, free of pin bones, with a cutting length having the curvature.