A photoacoustic diagnostic apparatus comprising: a photoacoustic probe comprising a light irradiation unit that irradiates light to a subject and a transducer that receives ultrasound generated from the subject and converts the ultrasound into an electric signal; a contact detection unit that detects whether the photoacoustic probe contacts the subject and is capable of moving to a first location protruding outwards from the photoacoustic probe and to a second location inserted more inwards toward the photoacoustic probe than the first location; a user input unit that receives an input signal from a user for the light irradiation unit to irradiate light and is capable of moving to a third location in which the input signal is not received and to a fourth location in which the input signal is received; characterised in that the photoacoustic probe further comprises: a movement restriction unit that selectively restricts a location movement of the user input unit based on a location of the contact detection unit; and an elastic member that pressurizes the contact detection unit to move from the second location to the first location; wherein the movement restriction unit comprises a first connection rod connected to the user input unit and a second connection rod which is connected to the contact detection unit and which includes an insertion portion into which at least a portion of the first connection rod can be inserted; wherein the first connection rod is configured to move in connection with the movement of the user input unit; and the second connection rod is configured to move in connection with the movement of the contact detection unit; wherein when the contact detection unit is located in the first location by the elastic member, the insertion portion is located outside a movement path of the first connection rod such that the first connection rod is restricted from being inserted into the insertion portion and the user input unit is restricted from moving from the third location to the fourth location, and wherein when the contact detection unit is located in the second location, the insertion portion is located in the movement path of the first connection rod such that the first connection rod is capable of being inserted into the insertion portion and the user input unit is capable of moving from the third location to the fourth location. a photoacoustic probe comprising a light irradiation unit that irradiates light to a subject and a transducer that receives ultrasound generated from the subject and converts the ultrasound into an electric signal; a contact detection unit that detects whether the photoacoustic probe contacts the subject and is capable of moving to a first location protruding outwards from the photoacoustic probe and to a second location inserted more inwards toward the photoacoustic probe than the first location; a user input unit that receives an input signal from a user for the light irradiation unit to irradiate light and is capable of moving to a third location in which the input signal is not received and to a fourth location in which the input signal is received; characterised in that the photoacoustic probe further comprises: a movement restriction unit that selectively restricts a location movement of the user input unit based on a location of the contact detection unit; and an elastic member that pressurizes the contact detection unit to move from the second location to the first location; a movement restriction unit that selectively restricts a location movement of the user input unit based on a location of the contact detection unit; and an elastic member that pressurizes the contact detection unit to move from the second location to the first location; wherein the movement restriction unit comprises a first connection rod connected to the user input unit and a second connection rod which is connected to the contact detection unit and which includes an insertion portion into which at least a portion of the first connection rod can be inserted; wherein the first connection rod is configured to move in connection with the movement of the user input unit; and the second connection rod is configured to move in connection with the movement of the contact detection unit; wherein when the contact detection unit is located in the first location by the elastic member, the insertion portion is located outside a movement path of the first connection rod such that the first connection rod is restricted from being inserted into the insertion portion and the user input unit is restricted from moving from the third location to the fourth location, and wherein when the contact detection unit is located in the second location, the insertion portion is located in the movement path of the first connection rod such that the first connection rod is capable of being inserted into the insertion portion and the user input unit is capable of moving from the third location to the fourth location.