A sensor, which is small and 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. The sensor is composed of a first board composed of a semiconductor by which a conducting part of the switch is formed, a second board composed of the semiconductor by which the conducting part of the switch is formed or an insulator by which a conducting part of the switch is formed, and a moving member having conductivity. The sensor having the switch function is provided by permitting either the first board or the second board to have a cavity-shaped part and by confining the moving member having conductivity by the first board and the second board. |