Ultrasonic detection device and ultrasonic diagnostic device

An ultrasonic detection device comprising:

• a capacitive electromechanical transducer including at least one cell that includes a first electrode and a second electrode disposed opposite from the first electrode, a space being between the first electrode and the second electrode;
• and
• an electric circuit for converting a current, which is output from the capacitive electromechanical transducer, into a voltage,
• wherein frequency characteristic of the capacitive electromechanical transducer has a high-pass characteristic having a first cutoff frequency with respect to a frequency,
• wherein frequency characteristic of the electric circuit has a low-pass characteristic having a second cutoff frequency with respect to the frequency, and
• wherein the second cutoff frequency is smaller than the first cutoff frequency so that the current output from the capacitive electromechanical transducer is input to the electric circuit and the frequency characteristic of the voltage output from the electric circuit, obtained by using both the frequency characteristic of the capacitive electromechanical transducer and the frequency characteristic of the electric circuit, has band-pass characteristic.