An access control device for controlling an access of a plurality of persons of a group of persons to an access area, comprising: a device for providing a plurality of biometric features of a plurality of persons of a group of persons, wherein each person is assigned a biometric feature, wherein the device comprises: a person counting device, which is configured to determine a number of persons in the group of persons in order to obtain a first number of persons; and a detection device, which is configured to detect the plurality of biometric features, to compare at least two biometric features of the plurality of biometric features, to determine a number of different biometric features in the plurality of biometric features in order to obtain a second number of persons, and to provide the plurality of biometric features for further processing, if the first number of persons matches the second number of persons; the access control device further comprising: an access gate, which comprises an entry door and an exit door; wherein the person counting device is configured to determine the number of persons in the group of persons between the entry door and the exit door; wherein the detection device is configured to detect the plurality of persons between the entry door and the exit door, and, in response to the detection of the plurality of persons between the entry door and the exit door, to detect the plurality of biometric features; and characterized in that the access control device comprises a signal transmitter, which is configured to emit a signal, in particular an acoustic signal or a visual signal, in direction of the group of persons, if the first number of persons does not match the second number of persons. a person counting device, which is configured to determine a number of persons in the group of persons in order to obtain a first number of persons; and a detection device, which is configured to detect the plurality of biometric features, to compare at least two biometric features of the plurality of biometric features, to determine a number of different biometric features in the plurality of biometric features in order to obtain a second number of persons, and to provide the plurality of biometric features for further processing, if the first number of persons matches the second number of persons; the access control device further comprising: an access gate, which comprises an entry door and an exit door; wherein the person counting device is configured to determine the number of persons in the group of persons between the entry door and the exit door; wherein the detection device is configured to detect the plurality of persons between the entry door and the exit door, and, in response to the detection of the plurality of persons between the entry door and the exit door, to detect the plurality of biometric features; and characterized in that the access control device comprises a signal transmitter, which is configured to emit a signal, in particular an acoustic signal or a visual signal, in direction of the group of persons, if the first number of persons does not match the second number of persons. an access gate, which comprises an entry door and an exit door; wherein the person counting device is configured to determine the number of persons in the group of persons between the entry door and the exit door; wherein the detection device is configured to detect the plurality of persons between the entry door and the exit door, and, in response to the detection of the plurality of persons between the entry door and the exit door, to detect the plurality of biometric features; and characterized in that the access control device comprises a signal transmitter, which is configured to emit a signal, in particular an acoustic signal or a visual signal, in direction of the group of persons, if the first number of persons does not match the second number of persons.