A collapsible pushchair frame or doll's pushchair frame, includes: two lateral frame bars with push bars and front wheel arrangements on the frame bars; two lateral support struts, each of which is pivotably fastened, by a respective joint to a frame bar, at a distance from the lower end of the bar and which have bearings for rear wheels on their lower ends lying towards the rear in relation to the articulation points; and a seat insert or reclining insert. At least one stabilizing rod is designed as a safety rod and divided by a knee joint. An adjusting device includes an actuating element (21) arranged under the insert in the pushchair frame is coupled to at least one part of the at least one stabilizing rod, the actuating element being used to at least raise the corresponding front part of the stabilizing rod (13a, 13b) comprising the knee joint (18).