An improved pacifier for a baby which is equipped with a chip-style thermo-sensitive resistor at the tip of the nipple thereof for detecting the oral temperature of a baby; and a liquid crystal display is disposed on the side of the rear portion of the pacifier for display of a detected temperature; and an antenna and a transmitter for delivery of alarm signals which can be received by an amplifying circuit of a receiver housed in a TV set or a stereo set to produce alarm or music or preset words so that parents or adults can be alarmed of the condition of a baby.