A medical diagnostic apparatus according to the present invention includes: a plurality of freeze instruction input units configured to receive a freeze command signal； a first storage unit which stores a plurality of observation images in chronological order； an identification unit which identifies the freeze instruction input unit； a second storage unit which stores a setting time to decide a selection designated time for selecting the observation image to be frozen on a display unit from the first storage unit, in association with each of the freeze instruction input units； a selection designated time deciding unit configured to decide the selection designated time for selecting the observation image to be frozen on the display unit based on an identification result and the setting time； and an image selection unit configured to select the observation image generated the selection designated time before or after receiving the command signal.
