A flow passage switching valve provided with a swing arm type valve
element comprises a housing formed with a first passage communicated with
an inlet port, a second passage communicated with an outlet port, a
bypass passage for providing communication between the first passage and
the second passage, an introduction port through which a fluid flowing in
the first passage is introduced into an external part, and a discharge
port through which the fluid introduced into the external part is
discharged into the second passage.