PURPOSE: To drill an accurate circular hole with a drill hammer even in the case where a tool receiver member is vibrated by restricting the transmission of the operation of a striking tool, and fixing the tool holder to a drill hammer fastening neck part.

CONSTITUTION: This tool holder to be connected to a tool receiver member 4 for a shaft tool provided with groove for drill hammer is formed of a covering fitting member 16 to be fixed to a fastening neck part 14 of the drill hammer and a shaft 24 to be engaged with inside of the tool receiver member 4 of the drill hammer. The shaft 24 is supported inside of the covering fitting member 16 freely to be rotated, and the shaft 24 has a means 26 to be engaged with the tool receiver member 4 for accompanying rotation. Furthermore, length of the shaft 24 is regulated so that the shaft never contact with strikers 7, 8.