A soft adhesive agent whose force occurring at the time of curing is small is
applied
between a rib and a PD, and after the curing of the soft adhesive agent, a hard
adhesive agent whose force occurring at the time of curing is large is applied
between the rib and a plate. Thus since a sensor portion is fixed to a main-body
base with two kinds of adhesive agents including the soft adhesive agent and the
hard adhesive agent, it is possible to suppress the positional offset of the sensor
portion at the time of its attachment, and it is possible to sufficiently ensure
reliability with respect to the temperature change as well.
