NOVELTY - The device has a homothetic conversion equation storer (3) storing a homothetic conversion equation for performing homothetic conversion of input and output parameters. A homothetic conversion parameter searcher (4) searches and establishes factors of the homothetic conversion equation using analysis data. An estimating polynomial calculator (5) calculates an estimating polynomial for estimating an output parameter value from an input parameter value by combining a function surface equation and the homothetic conversion equation for which the factors are established.    USE - Estimating polynomial generating device for calculating an estimating polynomial to estimate an output parameter value i.e. state quantity e.g. surface temperature of a wafer or a glass panel, online during execution of a process e.g. thermal process and plasma process, in a semiconductor manufacturing equipment, a flat panel display (FPD) manufacturing equipment and a solar cell manufacturing equipment.    ADVANTAGE - The device enables the calculation of the estimating polynomial so as to enable decrease in the probability of the calculation of an unrealistic estimated value in a region where the analysis data are scarce through an equation for a function surface that limits the relationship between the input parameter and the output parameter after a homothetic conversion, so that the estimating polynomial obtained from the analysis data, the equation for the function surface, and the homothetic conversion equation are limited by the function surface, thus enabling the thermal or plasma process in the manufacturing equipment to be easily performed.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for the following:    (1) an estimating device for calculating estimated values using an estimating polynomial, comprising an input parameter value acquirer    (2) an estimating polynomial generating method    (3) an estimating method for calculating estimated values using an estimating polynomial.    DESCRIPTION OF DRAWING(S) - The drawing shows a block diagram of an estimating polynomial generating device.    Analysis data storer (1)    Function surface storer (2)    Homothetic conversion equation storer (3)    Homothetic conversion parameter searcher (4)    Estimating polynomial calculator (5)