Mounted internally of a casing of a manipulating head assembly of an endoscope is a branching passage member to connect a base end of a biopsy channel with a biopsy channel entrance way and a suction passage. The branching passage member is retained in position by threaded engagement with a biopsy channel entrance pipe which is fitted in the biopsy channel entrance way. Further, the branching passage member is provided with restrictive members thereby to restrict movements of the branching member except a movement toward the biopsy channel entrance pipe when the branching member is pulled into the biopsy channel entrance way for engagement with the entrance pipe.
