A ship steering method to control a ship steering device so as to keep the hull of the ship sailing obliquely without turning, the ship steering device being of the type comprising: - a pair of left and right engines ; - rotation speed changing actuators independently changing engine rotation speeds (NA, NB) of the pair of left and right engines; - a pair of left and right outdrive devices respectively connected to the pair of left and right engines and rotating screw propellers so as to propel a hull; - forward/reverse switching clutches disposed between the engines and the screw propellers; - a pair of left and right steering actuators respectively independently rotating the pair of left and right outdrive devices laterally; - an operation means setting a traveling direction of a ship; - an operation amount detection means detecting the operation amount of the operation means ; and - a control device controlling the rotation speed changing actuators , the forward/reverse switching clutches , and the steering actuators so as to travel to a direction set by the operation means ; the ship steering device further comprising: - correction control start switch , and - a storage means , the method comprising the following steps: • operate joystick so as to make ship sail obliquely; • twisting joystick to generate a turning moment (MP) which balances with the turning moment M generated by the lifting power L; • turning correction control start switch on; • calculating the turning moment MP • detecting elevation angle (a) by an elevation angle sensor ; • calculating the propulsion powers TA and TB based on twisting amount of joystick or from the engine rotation speed; • calculating of dynamic pressure 1/2pV2 based on propulsion powers (TA, TB); • calculating of hull speed (V) based on dynamic pressure 1/2pV2; • determining correction value (K) based on formula K = MP/V2/C(a) wherein C(a) is a moment coefficient and a function of a; • displaying correction value (K); • storing K in storage means . - a pair of left and right engines ; - rotation speed changing actuators independently changing engine rotation speeds (NA, NB) of the pair of left and right engines; - a pair of left and right outdrive devices respectively connected to the pair of left and right engines and rotating screw propellers so as to propel a hull; - forward/reverse switching clutches disposed between the engines and the screw propellers; - a pair of left and right steering actuators respectively independently rotating the pair of left and right outdrive devices laterally; - an operation means setting a traveling direction of a ship; - an operation amount detection means detecting the operation amount of the operation means ; and - a control device controlling the rotation speed changing actuators , the forward/reverse switching clutches , and the steering actuators so as to travel to a direction set by the operation means ; - correction control start switch , and - a storage means , • operate joystick so as to make ship sail obliquely; • twisting joystick to generate a turning moment (MP) which balances with the turning moment M generated by the lifting power L; • turning correction control start switch on; • calculating the turning moment MP • detecting elevation angle (a) by an elevation angle sensor ; • calculating the propulsion powers TA and TB based on twisting amount of joystick or from the engine rotation speed; • calculating of dynamic pressure 1/2pV2 based on propulsion powers (TA, TB); • calculating of hull speed (V) based on dynamic pressure 1/2pV2; • determining correction value (K) based on formula K = MP/V2/C(a) wherein C(a) is a moment coefficient and a function of a; • displaying correction value (K); • storing K in storage means . <EOS>