The invention relates to a fuel tank for an internal combustion engine comprising a hollow body (1) which is made of a first plastic material (K) and receives fuel and an attachment part (A) fixed to said hollow body, wherein K and A are connected by means of two horizontal jointed surfaces. Said invention is characterised in that, the surface of the attachment part (A, 2) is made of a plastic material which is unweldable to the plastic material of the hollow body and one of two surfaces is provided with micropores in which the other plastic material penetrates in the form of appendices extendable therein.
