There are provided a sensor which is small, suitable for reflow soldering by automatic cleaning and automatic mounting, can be manufactured in batch, and has a switch function, and a manufacturing method of the sensor, and a portable telephone having the sensor built therein.There are provided a sensor having a switch function, the sensor being composed of a first substrate composed of a semiconductor by which a conducting part of the switch is formed, a second substrate composed of the semiconductor by which a conducting part of the switch is formed or an insulator by which the conducting part of the switch is formed, and a moving member having conductivity, wherein any of the first substrate and the second substrate has a cavity-shaped portion and the moving member having conductivity is confined by the first substrate and the second substrate, and a manufacturing method of the sensor, and an electronic device having the sensor built therein.