A transfer characteristic calculation apparatus for calculating a transfer characteristic of an imaging optical system includes a light source, a generation unit which generates a second signal by converting a first signal obtained by stretching an impulse signal on a space axis into a positive value using a light from the light source, a sensor which obtains an image that is output from the imaging optical system as an output signal when a light intensity distribution is inputted as the second signal, and a calculation unit which calculates the transfer characteristic of the imaging optical system by convolution of a third signal with the forth signal that is obtained by canceling a bias component of the output signal obtained by the sensor, the third being an impulse signal upon convolution with the first signal.