It is an object of the present invention to provide a pickup device for a stringed instrument which can take a piezoelectric signal for a tone of an acoustic stringed instrument. A stringed instrument is composed of a stringed instrument main body and a sensor mechanism. The stringed instrument main body is composed of one or more strings, a vibration plate used to radiate the vibration of each string as a sound wave, and a sensor mechanism that can make pressure contact with the vibration plate of the stringed instrument main body. The sensor mechanism has fixing means configured to be secured to the stringed instrument main body and a contact sensor member tightly contacted with the vibration plate directly or via an intermediate member.