A brake device includes an opposing-type caliper body, brake pads mounted in the caliper body, each pad liner that supports the brake pads, and each pad pusher that pushes each brake pad, wherein the brake pad includes protrusions protruding from both side surfaces thereof, wherein the caliper body includes each guide groove defined therein to guide each protrusion, wherein the brake pad moves guided by the guide grooves. The caliper body is of a mono block type.