Head protective airbag apparatus

An airbag has a bag main body and a connection member with a base side joined to the bag main body and a distal end side fixed to a circumferential window edge. The bag main body has end-side and normal inflation portions. A slit is formed between the end-side and normal inflation portions. The base side of the connection member is joined to the bag main body at a position on a front and upper side from the slit. The bag main body is pulled by the connection member that covers a vehicle exterior side of the end-side inflation portion, in which is inserted into the slit from the vehicle interior side toward the vehicle exterior side when the airbag is completely inflated, and a vicinity of a part of the end-side inflation portion, is oriented toward the vehicle interior side.