A monitoring camera which has a lock mechanism, which is capable to unlock a lens 1 even if power supply is stopped due to blackout. The lock mechanism includes a lock member 11 having a region 11b which is pushed by an operation member 3 in a state where a lock pin member 12 engages with the lens 1, a biasing member 13 biasing the lock member 11, and magnetic force generating units 10 generating magnetic forces by electro energization, to move against the biasing force so that the region 11c faces the operation member 3. While the magnetic forces are not generated in a non-electro energization state, the operation member 3 pushes the region 11b and thus moves the lock member 11 and the lock pin member 12 so that the lock pin member 12 is released from the lens 1.