In a chip pick-up process after dicing in an assembly process during manufacture of a semiconductor integrated circuit device it is an important subject to diminish a pick-up defect caused by the reduction in thickness of each chip which is proceeding in quick tempo. Particularly, bending of the chip peripheral portion caused by a peeling operation is very likely to induce cracking and chipping of the chip. In the present invention, to solve these problems, in case of peeling a chip from a dicing tape (adhesive tape) or the like while vacuum-chucking the chip by a chucking collet, the flow rate of a vacuum chucking system in the chucking collet is monitored to check a bent state of the chip before complete separation of the first chip from the adhesive tape.