A signal processing circuit includes a correction function determination section for performing correction function determination processing, and a correction processing section for performing correction processing. The correction processing is to correct first and second detection signals by using a correction function to thereby generate first and second corrected signals. The correction function is expressed as a coefficient matrix for converting a first column vector containing the first and second detection signals as elements into a second column vector containing the first and second corrected signals as elements. The correction function determination processing includes performing arithmetic processing using a plurality of pairs of values of the first and second detection signals to determine one or two provisional correction coefficients as the correction coefficients of the correction function.