To provide a lens holding means which has an impact resistance performance against external force in a lens optical system, in which time until the impact resistance performance is given is short, and has sufficient impact resistance performance even in a photographing state.

In the lens optical system, a lens 13 is held by a lens barrel 11 and electromagnetic force generated by a coil 12. An external acceleration is detected by an acceleration sensor 16. According to the detected signal, the magnitude of the electromagnetic force from the coil 12 is controlled. Thereby, holding force for the lens 13 is changed from strong hold to weak hold. This makes is possible to reduce external impact applied to the lens 13 and lens barrel 11 instantly. In addition, by disposing a cushioning material 18 in the lens barrel 11, the impact can be more effectively reduced.