A joining pin (3.2) with which two parts (1 and 2) made from a porous material, particularly wood or a wood-like material, are to be joined together, is anchored in the porous material at predetermined anchoring points (31, 33). For this purpose, a bore (4.2) with a closed inner end (41) is made in the parts (1 and 2). The shape of this bore (4.2) is so matched to the joining pin (3.2) that it can be introduced substantially without force expenditure into the bore and is positionable in a first position. At least one predetermined anchoring point (31, 33) between the joining pin (3.2) and the wall of the bore (4.2) is formed when pressure is built up by pressing the joining pin (3.2) with a pressing force (F) more deeply into the bore to a second position. Energy is supplied in a planned manner to the joining pin (3.2) so that at the predetermined anchoring points (31, 33) the thermoplastic material of the joining pin (3.2) is plasticized. The locally plasticized plastic material is pressed by the local pressure into the porous material of the parts and forms local, macroscopic anchors (10, 20). The joining pin (3.2) is, e.g., made entirely from a thermoplastic material and the energy for plasticizing is supplied thereto by ultrasonic vibration.