A child safety barrier (1) has a handle (8, 20, 21), which, when being operated, causes two upper ferrules (9, 10) to be fixed in an opening between two side posts (2, 3), as well as a pressure indicator which shows how great a pressure is provided against the side posts (2, 3). According to the invention, the pressure indicator is constructed as a pressure transducer in the form of a strain gauge (13) which is disposed on one of the upper ferrules (9). A signal processing circuit (16), which is powered from a battery (19), is connected to the strain gauge (13). The signal processing circuit (16) has a display unit which may be a light-emitting diode or a sound unit, which gives a signal when the pressure between the upper ferrules (9, 10) is sufficient. The display unit also shows whether the battery (19) is sufficient charged. The invention provides a pressure indicator which is more reliable than a mechanical pressure indicator, in particular after having been used for an extended period of time.