PURPOSE: To acquire knowledge by providing a step to record the information to generalize a fact base, a step of an induction reasoning and a step to input the assembling of a character to express a question and an answer necessary to the induction reasoning.

CONSTITUTION: When the number of the fact with an equal attribute to exist in two types of a fact base 2 exceeds a certain threshold, the application of the induction reasoning is automatically executed and the extraction of a rule to have the attribute of the fact at a conclusion part is tried. Then, in order to execute generalization and specialization necessary to the induction reasoning, the fact is divided into two types of the fact base of a positive fact base 3 and a negative fact base 4. Further, by asking a knowledge engineer or an expert a question concerning the fact of the conditions part in which the truth or falsehood is unclear only by the knowledge in a knowledge base 1 for the verification of the hypothesis of the induction reasoning, the generalization or the law of the knowledge can be executed. Thus, the knowledge can be acquired.