A laser point projecting device including a light source assembly that projects first and second positioning points respectively along two directions of a straight line. The laser point projecting device includes a housing part forming a sleeve around a body part. The body part and the housing part are displaceable relative to each other. The light source assembly is switched off when the body part is displaced to a first position along the direction of projecting the first positioning point; and the light source assembly is activated when the body part is displaced to a second position along the direction of projecting the second positioning point. The housing part has at least one opening at the end along the direction of projecting the first positioning point, and a hollow space formed between the end of the housing part close to the first positioning point and the body part.