A protector having a hollow part with a sensor that detects an object between two conductive parts. The two conductive parts having a space therebetween. The hollow part has a wall having a horseshoe shaped cross section. Both ends of the wall are connected with an installation base member. The two conductive parts including a conductive part having a convex shape and a conductive part having a concave shape. The conductive parts are positioned in a manner such that the space substantially has a V-shaped cross section and a uniform width in cross section. Both ends of the V-shaped cross section terminate on an inner surface of the wall.