A binding machine includes: a wire feeding unit; a curl forming unit; a butting part; a cutting unit; and a binding unit. The binding unit includes: a rotary shaft; a wire engaging body configured to move in an axis direction of the rotary shaft and to engage the wire in a first operation area in the axis direction, and to move in the axis direction and to twist the wire in a second operation area in the axis direction; a rotation regulation part; and a tension applying part configured to perform, in the second operation area, an operation of applying tension on the wire engaged by the wire engaging body in the first operation area. The tension applied to the wire is equal to or larger than 10% and equal to or smaller than 50% with respect to a maximum tensile load of the wire.