In this study, a method to reduce the tool approach mark due to the tool deflection by cutting force in ball end-milling operation is proposed. In order to reduce the approach marks, the influence of the tool deflection onto the machined surface is investigated. Characteristics of the tool approach mark are investigated based on the measured machined surfaces by a roughness tester. On the investigation, it is confirmed that the tool approach mark exists caused by the tool deflection and the tool deflection is copied onto the surface. A compensation method to reduce the tool approach mark by changing approaching point is proposed. It is also confirmed that the influence of the tool approach mark can be reduced by the proposed tool approach path offset.