To provide a sampling device in a geological survey by boring capable of securely cutting a geological sample taken into a sampling cylinder off the ground by pulling up a device main body, preventing its fall during pulling up or generation of disorder in the sample, and avoiding generation of disorder in taking it out of the sampling cylinder.

The device main body 1 is provide with a head cover 4, an outer cylinder 5, a center shaft 6, a guide block 7, a piston 8, a sampling cylinder 9 connected to the piston 8, and a clutch mechanism 10 to the center shaft 6 of the piston 8, it is composed so that by introducing pressure water into a cylinder chamber 11, the piston 8 is unlocked to be lowered till the sampling cylinder 9 gets into the ground E at a bottom part of a bored hole 3, the guide block 7 is composed so that a rubber ring 72 slidable to gas-tightly get in contact with an inner circumferential surface of the sampling cylinder 9 is sandwiched between a block main body 70 and a tightening ring 71, the upper side and the lower side inside the sampling cylinder 9 are gas-tightly shielded from each other, the center shaft 6 is composed to be parted to a long shaft main body 6a and a short lower shaft body 6b, and it is attached to the block main body 70 of the guide block 7 at a lower end part of the lower shaft body 6b.