A step-shaped drill bit comprising at least two stepped cutting edges that are axially provided, wherein - a cutting edge of a first step from a tip is formed so as to satisfy the following conditions: - a point angle (θ1) of the cutting edge (1 0) is larger than that of cutting edges (20, 30) of a second and subsequent step(s), so as to reduce a thrust resistance during a perforation compared with a case in which the first step cutting edge is formed such that the point angle (θ1) of the cutting edge is the same as that of the second and subsequent step(s), characterized in that - a number of blades is smaller than that of cutting edges (20, 30) of a second and subsequent step(s), so as to reduce a thrust resistance during a perforation compared with a case in which the first step cutting edge is formed such that the number of blades is the same as that of the second and subsequent step(s), and - a clearance angle (γ) of the cutting edge is equal to or larger than that of cutting edges (20, 30) of a second and subsequent step(s), so as to reduce a thrust resistance during a perforation compared with a case in which the first step cutting edge is formed such that the clearance angle (γ1) of the cutting edge is smaller than that of the second and subsequent step(s). - a cutting edge of a first step from a tip is formed so as to satisfy the following conditions: - a point angle (θ1) of the cutting edge (1 0) is larger than that of cutting edges (20, 30) of a second and subsequent step(s), so as to reduce a thrust resistance during a perforation compared with a case in which the first step cutting edge is formed such that the point angle (θ1) of the cutting edge is the same as that of the second and subsequent step(s), characterized in that - a number of blades is smaller than that of cutting edges (20, 30) of a second and subsequent step(s), so as to reduce a thrust resistance during a perforation compared with a case in which the first step cutting edge is formed such that the number of blades is the same as that of the second and subsequent step(s), and - a clearance angle (γ) of the cutting edge is equal to or larger than that of cutting edges (20, 30) of a second and subsequent step(s), so as to reduce a thrust resistance during a perforation compared with a case in which the first step cutting edge is formed such that the clearance angle (γ1) of the cutting edge is smaller than that of the second and subsequent step(s). - a point angle (θ1) of the cutting edge (1 0) is larger than that of cutting edges (20, 30) of a second and subsequent step(s), so as to reduce a thrust resistance during a perforation compared with a case in which the first step cutting edge is formed such that the point angle (θ1) of the cutting edge is the same as that of the second and subsequent step(s), characterized in that - a number of blades is smaller than that of cutting edges (20, 30) of a second and subsequent step(s), so as to reduce a thrust resistance during a perforation compared with a case in which the first step cutting edge is formed such that the number of blades is the same as that of the second and subsequent step(s), and - a clearance angle (γ) of the cutting edge is equal to or larger than that of cutting edges (20, 30) of a second and subsequent step(s), so as to reduce a thrust resistance during a perforation compared with a case in which the first step cutting edge is formed such that the clearance angle (γ1) of the cutting edge is smaller than that of the second and subsequent step(s).