Safety monitoring device for monitoring safety-related states in a passenger conveyor system , comprising: - a first and a second double contact relay , both of which, in each case in a manner controlled by a control voltage, switch a first normally open contact and a second normally open contact as well as a feedback contact synchronously with one other between an open and a closed relay state; - a first and a second controller each for determining properties of the passenger conveyor system correlated with a safety-related state and for generating the control voltages for the first and the second double contact relay depending on the determined properties; characterized in that a first safety monitoring switch arrangement for monitoring a first safety-related state and for correspondingly switching a first switching state within a safety monitoring chain of the passenger conveyor system and a second safety monitoring switch arrangement for monitoring a second safety-related state and for correspondingly switching a second switching state within the safety monitoring chain of the passenger conveyor system are formed by means of the two double contact relays and the two controllers ; the first safety monitoring switch arrangement comprising the first normally open contact of the first double contact relay and, connected in series therewith, the first normally open contact of the second double contact relay ; and the second safety monitoring switch arrangement comprising the second normally open contact of the first double contact relay and, connected in parallel therewith, the second normally open contact of the second double contact relay . - a first and a second double contact relay , both of which, in each case in a manner controlled by a control voltage, switch a first normally open contact and a second normally open contact as well as a feedback contact synchronously with one other between an open and a closed relay state; - a first and a second controller each for determining properties of the passenger conveyor system correlated with a safety-related state and for generating the control voltages for the first and the second double contact relay depending on the determined properties; a first safety monitoring switch arrangement for monitoring a first safety-related state and for correspondingly switching a first switching state within a safety monitoring chain of the passenger conveyor system and a second safety monitoring switch arrangement for monitoring a second safety-related state and for correspondingly switching a second switching state within the safety monitoring chain of the passenger conveyor system are formed by means of the two double contact relays and the two controllers ; the first safety monitoring switch arrangement comprising the first normally open contact of the first double contact relay and, connected in series therewith, the first normally open contact of the second double contact relay ; and the second safety monitoring switch arrangement comprising the second normally open contact of the first double contact relay and, connected in parallel therewith, the second normally open contact of the second double contact relay . <EOS>