An air conditioner for a vehicle includes: an air-blowing guide that includes a flexible connecting section that elastically deforms, and a pair of engaging sections that are arranged at both ends of the flexible connecting section, is arranged in a mixing region of a hot air and a cool air, and guides the hot air and the cool air; and a case that includes a protrusion that engages the engaging section in a state where the flexible connecting section is elastically deformed, the case in which the air-blowing guide is provided.