Wood such as spruce, maple, and hornbeam are retained in high pressure steam of pressure 0.2 to 1.6 MPa at 120 to 200°C for 1 to 60 minutes, and subsequently, cooled and dried to obtain a modified wood having superior acoustic properties and old wood-like appearance due to a change to a deep color tone. Since the conventional modification methods by chemical treatment using chemicals such as resorcin and formaldehyde are not used, the treatment steps are simple and a modified wood used as a material for musical instruments is obtained at low cost.