An abnormality detection device configured to detect an abnormality of a safety device (31, 32, 33) which is connectable to a safety controller and has a plurality of channels for outputting a signal to the safety controller according to a state, comprising: a connection unit, configured to connect with the safety controller; a determination unit configured to acquire, via the connection unit, an output of each of the plurality of channels of the safety device (31, 32, 33) from the safety controller, and configured to determine whether an abnormality occurs in the safety device (31, 32, 33) depending on whether the output of each of the plurality of channels is the same; an estimation unit configured to estimate, for the safety device (31, 32, 33) for which occurrence of the abnormality has been determined by the determination unit, the channel having an abnormal output; a display unit configured to display, on a display, a screen comprising an image showing a diagram of wiring between the safety controller and the safety device (31, 32, 33) for which the occurrence of the abnormality has been determined by the determination unit, wherein the channel estimated to have the abnormal output by the estimation unit is distinguished from other channels in the image; and a characteristic information storage unit configured to store characteristic information indicating a relationship between the state of the safety device (31, 32, 33) and the output of each channel, wherein for the safety device (31, 32, 33) for which the occurrence of the abnormality has been determined by the determination unit, the estimation unit is configured to use the stored characteristic information to estimate the channel having the abnormal output. a connection unit, configured to connect with the safety controller; a determination unit configured to acquire, via the connection unit, an output of each of the plurality of channels of the safety device (31, 32, 33) from the safety controller, and configured to determine whether an abnormality occurs in the safety device (31, 32, 33) depending on whether the output of each of the plurality of channels is the same; an estimation unit configured to estimate, for the safety device (31, 32, 33) for which occurrence of the abnormality has been determined by the determination unit, the channel having an abnormal output; a display unit configured to display, on a display, a screen comprising an image showing a diagram of wiring between the safety controller and the safety device (31, 32, 33) for which the occurrence of the abnormality has been determined by the determination unit, wherein the channel estimated to have the abnormal output by the estimation unit is distinguished from other channels in the image; and a characteristic information storage unit configured to store characteristic information indicating a relationship between the state of the safety device (31, 32, 33) and the output of each channel, wherein for the safety device (31, 32, 33) for which the occurrence of the abnormality has been determined by the determination unit, the estimation unit is configured to use the stored characteristic information to estimate the channel having the abnormal output.