To provide a compact and inexpensive laser theodolite.

In a laser theodolite having a collimating optical system consisting of an eyepiece 9, an objective lens 5 and an optical path dividing prism member arranged between the eyepiece 9 and the lens 5 and capable of collimating a target and a laser light source arranged in the vicinity of the prism member and capable of projecting laser light along the optical axis of the optical system, the prism member is a prism 40 obtained by joining a polyprism for erecting an image of a target and a rectangular prism having a polarizing film and the laser light source is arranged so that exiting laser light becomes linearly polarized laser light consisting of either one of a P component and an S component. Consequently the polarizing film of the rectangular prism has characteristics capable of transmitting the same component as a polarized component of linearly polarized light almost 100% and reflecting the other component light almost 100%.