A prism is provided with which the positional accuracy can be effectively enhanced. The prism includes: a prism body 2 having a bottom surface 2a and an inclined surface 2b connected to the bottom surface 2a; and an adhesive film 3 provided on the bottom surface 2a, the adhesive film 3 including a first layer portion positioned on a side facing the prism body 2 and a second layer portion 6 including at least one of an Au layer or an Sn layer, the first layer portion 5 and the second layer portion 6 directly or indirectly stacked.