An optical tomographic imaging apparatus acquires tomographic images of an object to be examined where the images are based on reference light multiplexed with return light returned from the object to be examined which has been irradiated by measurement light via a scanning unit. The optical tomographic imaging apparatus includes a splitting unit configured to split light irradiated from a light source into the measurement light and the reference light, and a focusing lens disposed on the optical path of the measurement light between the splitting unit and a scanning unit. In a state in which the object to be examined is to be irradiated by the measurement light, an optical path branching unit which transmits the measurement light is retracted from the optical path.
