PURPOSE: To open a space between panels and to expect complete locking by providing an interlock section to stop the turning of a panel member of a panel shutter, and releasing the stopping of the interlock section prior to the turning of the panel member.

CONSTITUTION: A lock claw 20 and an interlocking pin 21 are fixed to the surface of a panel section of a moving member 19 through a notched groove 18b of an out-frame 18, the lock claw 20 is interlocked with a lock pin 22 fixed to a jamb 17b to prevent the turning of the jamb 17b, the panel section is locked to the out-frame 18. The interlocking pin 21 is interlocked with an interlocking hole 23a of an arm 23. When the moving member 19 moves upward, the pin 22 is released by moving the lock claw 20 upward, the interlocking hole 23a of the arm 23 is pushed up by the interlocking pin 21, the jamb 17b is turned to a position indicated with a two point chain line. According to the constitution, an inclination is controlled by the movable quantity of the moving member 19, instability of the panel member is prevented during the rising and falling of the shutter, and locking can be completely made.