Provided is a driving motor controlling device of a construction machine, including a driving motor which is included in the construction machine having a swivel joint interposed between an upper body and a lower body, and is connected to a pump and a tank through the swivel joint, and a motor control valve which switches a state for connecting the pump and the tank to the driving motor such that the driving motor is controlled to a stop state, a normal rotation state, or a reverse rotation state, wherein the motor control valve has a neutral position for the stop state, a normal rotation position for the normal rotation state, and a reverse rotation position for the reverse rotation state, and is switched to the neutral position, the normal rotation position, or the reverse rotation position, based on a command from a control device manipulated by a operator and a pressure of an inflow side of hydraulic oil into the driving motor, wherein the motor control valve is disposed in the lower body in which the driving motor is disposed, and is integrally formed with the driving motor, and wherein, upon a warming up operation, the hydraulic oil discharged from the pump is circulated to the tank disposed in the upper body through the swivel joint and the motor control valve.