An image acquisition apparatus irradiates light from a light source to an inspection object, obtains a tomographic image of the inspection object on the basis of a combined beam obtained by combining a return beam from the inspection object due to the irradiated light and a reference beam corresponding to the light, and obtains a plane image of the inspection object on the basis of the return beam from the inspection object due to the irradiated light. The apparatus performs a first scanning process to main-scan the irradiated light when the tomographic image is obtained, performs a second scanning process to main-scan the irradiated light at a speed higher than that in the first scanning process when the plane image is obtained, and performs a third scanning process to sub-scan the irradiated light when each of the tomographic image and the plane image is obtained.
