An optical image measurement apparatus comprising: an interferometer configured to split low coherence light into signal light and reference light and configured to generate interference light by superposing the signal light that has passed through a measured object and the reference light that has passed through a reference optical path; a light guiding part configured to guide the generated interference light; a spectral part configured to divide the interference light emitted from an emission end of the light guiding part into spectra; a light-receiving part configured to receive the interference light divided into spectra and outputs a signal; a specifying part configured to specify a received-light amount of the interference light by the light-receiving part based on the output signal; a first changing part configured to change the relative position between the emission end and a light-receiving surface of the light-receiving part; a second changing part configured to change the light amount of the interference light projected onto the light-receiving part; a controller configured to control the first changing part and the second changing part based on the specified received-light amount and configured to lead the received-light amount of the interference light by the light-receiving part to a target value; and an image forming part configured to form an image of the measured object based on the results of the interference light received by the light-receiving part after the received-light amount has been led to the target value; characterized in that the controller is configured to cause the following first and second operations to be performed alternately, wherein the first operation controls the first changing part with reference to the received-light amount that is sequentially specified by the specifying part to change the relative position to increase, at least during an initial stage, the received-light amount to at least an upper limit in a predefined range; and wherein the second operation controls the second changing part to change the light amount to decrease the received-light amount to at least a lower limit in the predefined range, the controller further being configured to, when determining that the specified received-light amount decreases in response to a change in the relative position in the first operation, perform a third operation that causes the first changing part to change the relative position to the immediately preceding status of this change; and to then perform a fourth operation that causes the second changing part to change the light amount and leads the received-light amount to the target value. an interferometer configured to split low coherence light into signal light and reference light and configured to generate interference light by superposing the signal light that has passed through a measured object and the reference light that has passed through a reference optical path; a light guiding part configured to guide the generated interference light; a spectral part configured to divide the interference light emitted from an emission end of the light guiding part into spectra; a light-receiving part configured to receive the interference light divided into spectra and outputs a signal; a specifying part configured to specify a received-light amount of the interference light by the light-receiving part based on the output signal; a first changing part configured to change the relative position between the emission end and a light-receiving surface of the light-receiving part; a second changing part configured to change the light amount of the interference light projected onto the light-receiving part; a controller configured to control the first changing part and the second changing part based on the specified received-light amount and configured to lead the received-light amount of the interference light by the light-receiving part to a target value; and an image forming part configured to form an image of the measured object based on the results of the interference light received by the light-receiving part after the received-light amount has been led to the target value; characterized in that the controller is configured to cause the following first and second operations to be performed alternately, wherein the first operation controls the first changing part with reference to the received-light amount that is sequentially specified by the specifying part to change the relative position to increase, at least during an initial stage, the received-light amount to at least an upper limit in a predefined range; and wherein the second operation controls the second changing part to change the light amount to decrease the received-light amount to at least a lower limit in the predefined range, the controller further being configured to, when determining that the specified received-light amount decreases in response to a change in the relative position in the first operation, perform a third operation that causes the first changing part to change the relative position to the immediately preceding status of this change; and to then perform a fourth operation that causes the second changing part to change the light amount and leads the received-light amount to the target value.