A depth image acquisition apparatus and a method of acquiring depth information are provided. The method of acquiring depth information includes: sequentially projecting, to a subject, N different beams of light emitted from a light source for a time period including an idle time for each of the N different beams of transmitted light, where N is a natural number that is equal to or greater than 3; modulating, using a light modulation signal, beams of reflected light that are obtained by reflection of the N different beams from the subject; obtaining N phase images corresponding to the N different beams of light by capturing, using a rolling shutter method, the modulated beams of reflected light; and obtaining depth information by using the obtained N phase images.