To provide a jet propulsion type planing boat, in which steering of the boat can be maintained and the steering can be controlled depending on the occasions of ahead and astern even if water volume jetted from a water jet pump is decreased by operating a throttle to be turned off, and which is easily manufactured and does not increase the weight.

The jet propulsion type planing boat propels by jetting the water from a rear jet port 21K, detects the off operation of the throttle together with the steering, and temporally increases a speed of an engine E, so that the steering function can be maintained at the time of the off operation of the throttle. A reverse operation detecting sensor Sr for detecting a reverse operation is arranged to detect the steering state and the off operation of the throttle. When a signal indicating the reverse operation is obtained from the reverse operation detecting sensor Sr, it is determined whether a speed of the boat is not more than a predetermined speed or not. If the speed is not more than the predetermined speed, the engine speed is temporally increased.