A contact probe includes a first plunger, a second plunger, and a coil spring. The coil spring is disposed outside the first plunger, and urges the first plunger and the second plunger in a direction away from each other. The first plunger and the second plunger are fitted to each other so as to be slidable with respect to each other. The first plunger includes a large diameter part, and a small diameter part provided on a proximal end side of the large diameter part. The small diameter part is fitted into the second plunger. The coil spring includes a close winding part on a side of the second plunger. Adjacent lines of the close winding parts are brought into close contact with each other and come into electrical contact with each other at least in a compressed state of the coil spring.