An image-pickup apparatus includes an exposure condition calculator configured to calculate an exposure condition of an image sensor determined by accumulation time of the image sensor, an amplification amount and an aperture value of an image signal, and an image generator configured to generate a high dynamic range image. When the plurality of exposure conditions have equal exposure differences, the exposure condition calculator changes the accumulation time so as to follow a change of the object brightness from a first value to a second value, and the exposure condition calculator calculates the plurality of exposure conditions by fixing the accumulation time and by changing the amplification amount so as to follow a change of the object brightness from a third value smaller than the first value to a fourth value smaller than the second value.