Building block for a construction toy set

Building block for a construction toy set, comprising a base body extending in a longitudinal direction, in a transverse direction transverse to the longitudinal direction and in a vertical direction transverse to the longitudinal direction and transverse to the transverse direction, which is penetrated in the vertical direction by a passage opening and from which a first axle element projects in the longitudinal direction and a second axle element projects in the transverse direction,

• characterized in that
• the base body is formed from two subcomponents which each hold an axle element, wherein each subcomponent comprises a connecting surface for abutment against the connecting surface of the corresponding other subcomponent, and wherein a male positive-locking element projects from the connecting surface of one subcomponent and, in the assembled state of the base body, is inserted into a corresponding female positive-locking element which is molded into the connecting surface of the other subcomponent;
• wherein the connecting surface of each subcomponent extends over a step with an upper side delimiting the step in or against the vertical direction and an abutment surface delimiting the step at right angles to the upper side.