To provide a hole machining method of a plate type member capable of preventing lowering in strength of the plate type member on which a hole is machined and the plate type member on which the hole is machined under the method.

Hole machining is carried out on a glass pane 201 by using a hole machining device 200. The hole machining device 200 is furnished with a lower side core drill 202, an upper side core drill 203 and a seamer 207. The lower side core drill 202 has a blade part 204, the upper side core drill 203 has a blade part 205 and the seamer 207 has a blade part 208. A thread surface 211 is formed roughly coaxially with straight holes 209, 210 from an upper surface of the glass pane 201 by the blade part 208 of the seamer 207 on the glass pane 201 in the neighborhood of the upper surface of which a step difference 206 is produced, and the step difference 206 is removed.