A flexible circuit board for being inserted into an in-vivo imaging device is provided. The flexible circuit board may include a plurality of flexible installation units connected to one another through flexible connection units. The flexible installation units may be capable of having electrical components disposed thereon at a size suitable for being included in an in-vivo imaging device which may be inserted into a body lumen, e.g., a capsule endoscope. An in-vivo imaging device which may enclose such a full-flexible circuit board is also provided.