PURPOSE: To reduce noise by providing an exhaust housing for forming a gas cushion for preventing water from flowing into an exhaust passage of an engine through a discharge means in non-operating, in a power operated surfboard for injecting water rearward by the rotation of an impeller by the engine.

CONSTITUTION: In a surfboard 10, a cable 11 having a control grip 14 for assisting an operator to be supported and for controlling a throttle is provided on a main part having an approximately flat upper surface 12. An engine 32, an impeller 66 to be rotated in an impeller housing 34 by power, and various units related to them are housed in a relative short and erected rear part 13. An exhaust housing 33 seated and fixed on the floor 21 of a hollow bulkhead of a main body is airtightly fixed in the impeller housing 34, and this exhaust housing 33 forms a gas cushion for preventing water flowing into an exhaust pipe part 62 of the engine 32 through a passage 74 when the surfboard 10 is not operated.