PURPOSE: To obtain simply a photographing reacting state by a single operation without barrier opening/closing operation by interlocking a barrier with the forward motion of a photographing optical system to open the barrier.

CONSTITUTION: In order to open the barrier from the position (dashed line 6a') of the lower end of the barrier at the time of reference photographing status leading in a bodytube cover 5, i.e. the closed position of the barrier, contact between the lower end 6a' of the barrier and the inclined edge 7a of an operation member 7 for opening/closing the barrier is released by moving the operation member 7 to the right along long holes 7e. 7f. Consequently, the barrier 6 is turned to the opened status by a spring. Namely, the barrier 6 is rotated and closed by pushing in the cover 5, and on the contrary, opened by pulling out the cover 5. Thus, the barrier 6 is opened/closed by using the abutting motion of the inclined surface 7a of the member 7.