PURPOSE: To permit the exact pop-up of a cloth bag without direct contact of explosive gas with the cloth bag at the time of ignition by housing an explosive- charged portion and a dye powder-filled cloth bag in a container through a pistonlike part.

CONSTITUTION: A slender container 1 is housed with a cloth bag 19 charged with a dye for sea marking, and said cloth bag 19 is designed to pop up from the container 1 when the sea marker lands on the sea water. In short, when the sea marker lands on the sea water, the sea water enters a sea water cell 8 to actuate the cell, an ignition ball 6 is fired, an explosive 5 is burned, a pistonlike part 13 provided in a short cylinder 10 is let off, and then the cloth bag 19 is popped up from the container. Then, the dye in the cloth bag floating on the sea surface is dissolved into the sea water to color the sea water in its vicinity.