The invention relates to a monitor device for monitoring the closed or open state of an article, the monitor device being in the form of an electronic circuit comprising a button closure system comprising two rows of elements (11, 12, 13, 14, 21, 22, 23, 24) made of electrically conductive material, each element of one row being couplable and un-couplable with an element of the other row. A detector-and-signaling device is connected firstly to at least one of the elements, referred to as a “first terminal” (21), and secondly to at least one of the other elements, referred to as a “second terminal”. The detector-and-signaling device (4) is configured to detect the state of electrical continuity between the first and second terminals (21, 24), and to issue a signal as a function of said detected continuity state. In a direction parallel to the rows of elements when said elements are in the coupled state, the first terminal (21) and the second terminal (24) are spaced apart from each other by at least one element (22, 23) of the button closure system (I5), said at least one element (22, 23) having no electrical connection with said terminals (21, 24) when the elements of the button closure system (I5) are in the uncoupled state.