Theft-protection device for bicycles

The invention relates to an anti-theft device for bicycles, which comprise a bicycle frame and a steering column mounted on the bicycle frame for steering the bicycle, which steering column is provided for a rotationally fixed coupling of a bicycle handlebar with a fork for a front wheel, having a separating means for neutralising the rotationally fixed coupling. With the invention is presented an anti-theft device for bicycles, which comprise a bicycle frame () and a steering column () mounted on the bicycle frame () for steering the bicycle, which steering column is provided for a rotationally fixed coupling of bicycle handlebars () with a fork () for a front wheel (), having a separating means for nuetralising the rotationally fixed coupling, wherein a coupling piece () or a connecting element () is provided as separating means, which divides the steering column () into two parts () and produces the rotationally fixed coupling of these steering column parts () in a first state and neutralises it in a second state.