The present invention relates to a case for a smart mobile device capable of improving the accident prevention and the efficiency of work by freeing two hands in utilizing a smart mobile device in industrial sites. The case for a smart mobile case comprises a neck line for support hung around the neck and having a coupling ring on both ends; a waist fixing belt mounted around the waist and having a coupling ring on both ends; a first supporting plate connected to the coupling ring and having a rectangular shape; a second supporting plate connected to the first supporting plate and having a rectangular shape capable of adjusting the angle; and a third supporting plate connected to the second supporting plate and having a rectangular shape connected to the coupling ring of the waist fixing belt.
