A cutting machine for cutting a window covering, wherein the window covering includes a first rail, a covering material, and a second rail, comprising: a machine base having a sustaining face for putting the window covering thereon; and a cutting device provided on the machine base, and including a cutter, which is controllable to reciprocate in a direction substantially perpendicular to the sustaining face, wherein the cutter has a blade edge, and an angle is formed between the blade edge and the sustaining face to cut the first rail, the covering material, and the second rail in sequence, characterized in that: the machine base is provided with a non-rigid pad, and the sustaining face is formed on the non-rigid pad; wherein the machine base further includes a rigid board and a guiding board; the non-rigid pad and the guiding board are fixed to the rigid board, and a cutting slot is formed between non-rigid pad and the guiding board for the cutter to pass therethrough; the rigid board is provided with a discharging opening, which is lower than the sustaining face; wherein the guiding board is fixed to the rigid board in an oblique direction and has a guiding surface which slopes towards the discharging opening; and a cut-off part of the window covering after being cut leaves the machine base through the guiding board and the discharging opening in sequence. a machine base having a sustaining face for putting the window covering thereon; and a cutting device provided on the machine base, and including a cutter, which is controllable to reciprocate in a direction substantially perpendicular to the sustaining face, wherein the cutter has a blade edge, and an angle is formed between the blade edge and the sustaining face to cut the first rail, the covering material, and the second rail in sequence, characterized in that: the machine base is provided with a non-rigid pad, and the sustaining face is formed on the non-rigid pad; wherein the machine base further includes a rigid board and a guiding board; the non-rigid pad and the guiding board are fixed to the rigid board, and a cutting slot is formed between non-rigid pad and the guiding board for the cutter to pass therethrough; the rigid board is provided with a discharging opening, which is lower than the sustaining face; wherein the guiding board is fixed to the rigid board in an oblique direction and has a guiding surface which slopes towards the discharging opening; and a cut-off part of the window covering after being cut leaves the machine base through the guiding board and the discharging opening in sequence. the machine base is provided with a non-rigid pad, and the sustaining face is formed on the non-rigid pad; wherein the machine base further includes a rigid board and a guiding board; the non-rigid pad and the guiding board are fixed to the rigid board, and a cutting slot is formed between non-rigid pad and the guiding board for the cutter to pass therethrough; the rigid board is provided with a discharging opening, which is lower than the sustaining face; wherein the guiding board is fixed to the rigid board in an oblique direction and has a guiding surface which slopes towards the discharging opening; and a cut-off part of the window covering after being cut leaves the machine base through the guiding board and the discharging opening in sequence.