Electromechanical transducer and photoacoustic apparatus

The present invention provides an electromechanical transducer which can prevent light from being incident on a receiving face, without deteriorating mechanical characteristics of a vibration film. The electromechanical transducer has at least one cell 2 in which the vibration film 7 containing one electrode 8 out of two electrodes 3 and 8 that are provided so as to interpose a space 5 therebetween is vibratably supported. The electromechanical transducer has a stress relaxation layer 9 formed on the vibration film 7, which has an acoustic impedance matching that of the vibration film 7, and has a light reflection layer 6 formed on the stress relaxation layer 9.