A steering control device of a marine vessel, wherein the marine vessel includes a hull, a propulsion device that propels the hull, a steering wheel having a regulated rotatable angle, and a turning driver that changes a turning angle of the propulsion device (15A, 15B) the steering control device comprising: at least one memory that stores a set of instructions; and at least one processor that executes the instructions to: control a steering mode of the marine vessel, the steering mode including a normal steering mode which allows the marine vessel to be steered by a rotation operation of the steering wheel, and an automatic steering mode which allows the marine vessel to be automatically steered without depending on the rotation operation of the steering wheel; acquire a rotation angle position of the steering wheel; acquire an actual turning angle of the propulsion device; characterized in that, said at least one processor further executes the instructions to: determine, based on the acquired rotation angle position, whether or not rotation of the steering wheel is stopped; and when performing the control of the steering mode, during return control to shift the steering mode from the automatic steering mode to the normal steering mode, execute first control to control the turning driver so as to reduce deviation between a turning angle corresponding to the acquired rotation angle position and the acquired actual turning angle in a case where it is determined that the rotation of the steering wheel is stopped. at least one memory that stores a set of instructions; and at least one processor that executes the instructions to: control a steering mode of the marine vessel, the steering mode including a normal steering mode which allows the marine vessel to be steered by a rotation operation of the steering wheel, and an automatic steering mode which allows the marine vessel to be automatically steered without depending on the rotation operation of the steering wheel; acquire a rotation angle position of the steering wheel; acquire an actual turning angle of the propulsion device; characterized in that, said at least one processor further executes the instructions to: determine, based on the acquired rotation angle position, whether or not rotation of the steering wheel is stopped; and when performing the control of the steering mode, during return control to shift the steering mode from the automatic steering mode to the normal steering mode, execute first control to control the turning driver so as to reduce deviation between a turning angle corresponding to the acquired rotation angle position and the acquired actual turning angle in a case where it is determined that the rotation of the steering wheel is stopped. control a steering mode of the marine vessel, the steering mode including a normal steering mode which allows the marine vessel to be steered by a rotation operation of the steering wheel, and an automatic steering mode which allows the marine vessel to be automatically steered without depending on the rotation operation of the steering wheel; acquire a rotation angle position of the steering wheel; acquire an actual turning angle of the propulsion device; characterized in that, said at least one processor further executes the instructions to: determine, based on the acquired rotation angle position, whether or not rotation of the steering wheel is stopped; and when performing the control of the steering mode, during return control to shift the steering mode from the automatic steering mode to the normal steering mode, execute first control to control the turning driver so as to reduce deviation between a turning angle corresponding to the acquired rotation angle position and the acquired actual turning angle in a case where it is determined that the rotation of the steering wheel is stopped. determine, based on the acquired rotation angle position, whether or not rotation of the steering wheel is stopped; and when performing the control of the steering mode, during return control to shift the steering mode from the automatic steering mode to the normal steering mode, execute first control to control the turning driver so as to reduce deviation between a turning angle corresponding to the acquired rotation angle position and the acquired actual turning angle in a case where it is determined that the rotation of the steering wheel is stopped.