An imaging apparatus generates a cross-sectional image in the longitudinal direction inside a body cavity (e.g., blood vessel) by using an interference signal. The apparatus includes an obtaining unit for obtaining line data, and a judgment unit for judging whether or not the optical probe unit operates in a normal state based on existence or non-existence of intensity change in at least a portion of signals within the obtained line date, based on existence or non-existence of change of position in the depth direction in which the portion of signals appear, or based on change quantity per unit time with respect to the position in the depth direction in which the portion in the depth direction of signals appear.
