PROBLEM TO BE SOLVED: To provide an optical tomographic imaging apparatus which is capable of suppressing an influence of variation in wavelength sweep rate per period of light emitted from a light source.SOLUTION: In respect to a measurement interference signal which is outputted from a light receiving element when light from a light source is periodically swept, the optical tomographic imaging apparatus uses, in each period, rescaling data stored in a memory and a wavelength sweep rate of the light source or its variation in the period obtained from wavelength sweep rate detection means, to convert the measurement interference signal in the period sampled at equal time intervals to a measurement interference signal sampled at equal frequency intervals and executes Fourier transform processing of performing Fourier transform of the converted measurement interference signal sampled at equal frequency intervals.
