A plasma processing machine comprising: a plasma head (14, 14', 14") configured to generate a plasma gas and eject the plasma gas from a nozzle; a head moving device configured to move the plasma head (14, 14', 14"); and an attachment mechanism for detachably attaching the plasma head (14, 14', 14") to an attachment section of the head moving device, an attaching surface provided at the attachment section and extending in a first direction and a second direction perpendicular to the first direction, wherein the attachment mechanism includes an attached surface provided at the plasma head (14, 14', 14") and coming into contact with the attaching surface in a state in which the plasma head (14, 14', 14") is attached, a first engaging section provided at a portion on one side of the attachment section in the first direction, and a second engaging section provided at a portion on the other side, and a first engaged section engaging with the first engaging section and a second engaged section engaging with the second engaging section, the first and the second engaged sections being provided at the plasma head (14, 14', 14"), the first engaging section is configured to lock the first engaged section so as to prohibit displacement of the plasma head (14, 14', 14") with respect to the attachment section to one side in the first direction, the second engaging section has a biasing mechanism that biases the second engaged section toward one side in the first direction, and wherein the plasma processing machine further comprises a second-direction displacement prohibiting mechanism configured to prohibit displacement of the plasma head (14, 14', 14") in the second direction in a state in which the first engaging section and the first engaged section are engaged and the second engaging section and the second engaged section are engaged characterized in that: the attachment mechanism is configured to complete attachment of the plasma head (14, 14', 14") by moving the plasma head (14, 14', 14") such that the second engaged section is moved in a third direction that intersects both the first direction and the second direction in a state in which the first engaged section is locked to the first engaging section, and bringing the attached surface into contact with the attaching surface to engage the second engaged section with the second engaging section. a plasma head (14, 14', 14") configured to generate a plasma gas and eject the plasma gas from a nozzle; a head moving device configured to move the plasma head (14, 14', 14"); and an attachment mechanism for detachably attaching the plasma head (14, 14', 14") to an attachment section of the head moving device, an attaching surface provided at the attachment section and extending in a first direction and a second direction perpendicular to the first direction, wherein the attachment mechanism includes an attached surface provided at the plasma head (14, 14', 14") and coming into contact with the attaching surface in a state in which the plasma head (14, 14', 14") is attached, a first engaging section provided at a portion on one side of the attachment section in the first direction, and a second engaging section provided at a portion on the other side, and a first engaged section engaging with the first engaging section and a second engaged section engaging with the second engaging section, the first and the second engaged sections being provided at the plasma head (14, 14', 14"), the first engaging section is configured to lock the first engaged section so as to prohibit displacement of the plasma head (14, 14', 14") with respect to the attachment section to one side in the first direction, the second engaging section has a biasing mechanism that biases the second engaged section toward one side in the first direction, and wherein the plasma processing machine further comprises a second-direction displacement prohibiting mechanism configured to prohibit displacement of the plasma head (14, 14', 14") in the second direction in a state in which the first engaging section and the first engaged section are engaged and the second engaging section and the second engaged section are engaged