[Objective]The amount of time required to complete reception of photoacoustic signals and ultrasonic wave signals is shortened in a tomographic image generating apparatus.[Constitution]A trigger control circuit (28) outputs a light trigger signal to cause light to be irradiated onto a subject. A sampling control circuit (29) outputs a sampling trigger signal. An A/D converting means (22) initiates sampling of photoacoustic signals and stores sampled photoacoustic signals in a reception memory (23). The trigger control circuit (28) outputs an ultrasonic wave trigger signal in a state in which sampling by the A/D converting means (22) is being conducted, and causes ultrasonic waves to be transmitted toward the subject. The A/D converting means (22) samples reflected acoustic signals continuous with the photoacoustic signals, and stores sampled reflected acoustic signals in the reception memory (23). A photoacoustic image generating means (25) and an ultrasound image generating means (26) generate a photoacoustic image and an ultrasound image based on data stored in the reception memory (23).
