An insulating ratchet wrench includes a wrench body, a ratchet assembly, a main insulator and a knob. The wrench body is covered with the main insulator. The main insulator has a first insulating ring and a second insulating ring. The first insulating ring has a main annular wall and a sub annular wall. The knob has a main annular groove and a sub annular groove. Under this arrangement, the knob is assembled with the main insulator by the main annular groove and the sub annular groove sleeving onto the main annular wall and the sub annular wall respectively so as to form an overlapping structure between the ratchet assembly and the knob. When a user rotates the knob or holds the wrench body near the ratchet assembly, the main insulator avoids an electric shock in a saltatory conduction manner from a charged object via the ratchet assembly.