A parameter calculating apparatus includes a signal generator that generates at least two input signals which each contain different frequency components; a signal inputting unit that inputs the input signals generated by the signal generator to respective ports of a test object at the same time; a frequency component deconstructing unit that deconstructs an output signal which is obtained by synthesizing the input signals input by the signal inputting unit and output from an output port into the frequency components; and a parameter calculator that calculates parameters which indicate transfer coefficients among ports of the test object based on output values of the frequency components obtained via the deconstruction performed by the frequency component deconstructing unit and on input values of the frequency components of the input signals input at the same time to a plurality of ports.