To provide a method for quickly and simply measuring the number of bacteria in a food.

This method for measuring the number of the bacteria living in a test specimen such as a food comprises crushing a plurality of standard specimen which are the same kind of the test specimen, subjecting the obtained standard specimen extract to a real time PCR using rpoB gene as a target to determine a Ct value, practically sowing the standard specimen extract or its diluted liquid on a culture medium, measuring the concentration of the bacteria, plotting the Ct values and the concentrations of the bacteria to make a calibration curve, similarly crushing the test specimen, subjecting the obtained specimen extract to a real time PCR in the same conditions to determine a Ct value, measuring the concentration of bacteria in response to the Ct value with the calibration curve, and calculating the total number of the bacteria.