A safety and burglarproof lock comprises a handle seat having a front sheet, a rear sheet, two lateral sheets; each of the front sheet and rear sheet having at least one lock hole; each of the two lateral sheets having a slot, each of the front, rear and lateral sheets having a plurality of through holes; a teethed wheel having a teethed protrusion, a protrusion cylinder protruded from a front end of the teethed protrusion and a post protruded from the front end of the teethed protrusion and aside the protrusion cylinder; the teethed wheel having a rectangular hole; the protrusion cylinder being engaged to the through hole of the front sheet; a latch having a guide groove and a stud; an elastic unit for connecting the stud and the post; a lock core having a keyhole and outer threads; and a horizontal handle having a spindle.