To provide an apparatus for fixing a simplified roof for a small marine vessel with improved safety and appearance by reducing a height dimension above an upper face plate of a hull while positively fixing a support frame.

In this apparatus for fixing the simplified roof for the small marine vessel to the hull, the simplified roof detachably mounted to the hull of the small marine vessel to cover the upper part of a boarding section has the support frame e with the base end fixed to the upper face plate b of the hull, and a shading sheet d stretched over the support frame e. The fixing apparatus is provided with a fixing apparatus body 2 fittingly fixed into a through-hole b1 formed in the upper face plate b; a through-hole 3 provided in the fixing apparatus body to insert the base end side of the support frame e through; and a claw member 4 and an operating member 6 capable of locking the base end side of the support frame e inserted through the through-hole 3 and releasing the lock.