An apparatus for replacing a welding tip installed in a robot arm and configured to replace the welding tip of a welding gun installed on a ground, the apparatus comprising: welding tip removal means combined with the robot arm; welding tip mounting means combined with one side of the welding tip removal means; and welding tip supply means spaced apart from the welding gun at a specific distance and configured to supply a welding tip to the welding tip mounting means; characterised in that the welding tip mounting means is configured to comprise: a housing combined with one side of the welding tip removal means; a cylinder combined with an end of the housing; and a finger unit provided within the housing and driven by the cylinder; wherein the finger unit is configured to comprise: a combination tool placed within the housing and configured to have one end combined with the cylinder; a connection tool one end of which is rotatably combined with the other end of the combination tool; an actuation finger configured to have one end rotatably combined with the other end of the connection tool and to have a central part hinged and combined with a specific location within the housing; and a fixation finger combined with a specific location within the housing so that the fixation finger is placed under the actuation finger. welding tip removal means combined with the robot arm; welding tip mounting means combined with one side of the welding tip removal means; and welding tip supply means spaced apart from the welding gun at a specific distance and configured to supply a welding tip to the welding tip mounting means; characterised in that the welding tip mounting means is configured to comprise: a housing combined with one side of the welding tip removal means; a cylinder combined with an end of the housing; and a finger unit provided within the housing and driven by the cylinder; wherein the finger unit is configured to comprise: a combination tool placed within the housing and configured to have one end combined with the cylinder; a connection tool one end of which is rotatably combined with the other end of the combination tool; an actuation finger configured to have one end rotatably combined with the other end of the connection tool and to have a central part hinged and combined with a specific location within the housing; and a fixation finger combined with a specific location within the housing so that the fixation finger is placed under the actuation finger. a housing combined with one side of the welding tip removal means; a cylinder combined with an end of the housing; and a finger unit provided within the housing and driven by the cylinder; wherein the finger unit is configured to comprise: a combination tool placed within the housing and configured to have one end combined with the cylinder; a connection tool one end of which is rotatably combined with the other end of the combination tool; an actuation finger configured to have one end rotatably combined with the other end of the connection tool and to have a central part hinged and combined with a specific location within the housing; and a fixation finger combined with a specific location within the housing so that the fixation finger is placed under the actuation finger. a combination tool placed within the housing and configured to have one end combined with the cylinder; a connection tool one end of which is rotatably combined with the other end of the combination tool; an actuation finger configured to have one end rotatably combined with the other end of the connection tool and to have a central part hinged and combined with a specific location within the housing; and a fixation finger combined with a specific location within the housing so that the fixation finger is placed under the actuation finger.