1. An apparatus for segmenting a text into a plurality of intervals, comprising: a topic model storage device that stores a topic model representing a semantic coherence; a model base topic segmentation section that segments the text in association with a topic, using the topic model stored in the topic model storage device; a parameter estimation section that estimates a parameter using a result of segmentation of the text by the model base topic segmentation section as training data, the parameter being used in segmenting the text based on detection of a change point in word distribution in the text; and a change point detection topic segmentation section that segments the text, based on detection of a change point of word distribution in the text, using the parameter estimated by the parameter estimation section.