SENSOR

PROBLEM TO BE SOLVED: To provide a sensor, in which the terminal used for extracting an electrical signal to the outside, can be assembled with satisfactory accuracy and in which its assembling operation can be performed simply. SOLUTION: In an oxygen sensor 1, connector terminals 30 are fixed to a first holder 40, in such a way that the first holder 40 is sandwiched above and below in between the locking parts 33a of the connector terminals 30 and element contact parts 31. That is to say, since the connector terminals 30 are assembled to the first holder 40 independently of a detection element 2, the connecting operation of the detecting element 2 to a terminal unit is completed, when the terminal unit assembled in advance in this manner is connected to the detecting element 2, in a state of being fixed to a main fitting 7, in advance. As a result, the assembling operation of the oxygen sensor 1 is facilitated.