A mouse with a built-in laser pointer including a mouse body, a first holding portion, a second holding portion, a laser source and a laser-emitting button is provided. Both the first holding portion and the second holding portion are pivotally connected to the mouse body. The laser source is disposed on either the first or the second holding portion. The laser-emitting button disposed on one of the mouse body, the first and the second holding portions activates the laser source. When the first and the second holding portions are parallel, the mouse with a built-in laser pointer controls a cursor's movement on a computer screen. When the first holding portion and the second holding portion are relatively open, the user can hold either the first or the second holding portion for operating the laser-emitting button for the laser source to emit laser beams.