An event estimation system includes an upper device, and a lower controller device including first circuitry that acquires operation information of a control target device connected to the lower controller device, estimates a presence or absence of an abnormality based on the operation information, holds the operation information for a certain time period, and transmits, based on the presence or absence of an abnormality and to the upper device, the operation information related to the estimation of the presence or absence of the abnormality. The upper device has second circuitry that receives the operation information from the lower controller device, and operates according to the presence or absence of the abnormality, inputs, using an upper neural network model, the operation information, output event information, and estimates an event.