There are provided an apparatus and a method for compressing data, an apparatus and a method for analyzing data and a data management system, which are capable of compressing a huge amount of data and accurately reproducing the characteristics of the original data from the data obtained by the compression. The data compressing apparatus includes detection means 4 for detecting a multiplicity of data sets, each of which includes n parameter values that vary according to an operation of an object (during the operation of the object), where n is a natural number; and data compressing means 6 for compressing the multiple data sets by inputting the multiple data sets detected by the detecting means into an n-dimensional space, arranging a predetermined number of neurons which are smaller in number than the multiple data sets in the n-dimensional space, carrying out unsupervised learning used for a neural network on the neurons, and converting the multiple data sets into a neuron model parameter characterizing a neuron model obtained by the unsupervised learning.