1. An error compensation method for multi-axis controlled machines comprising: generating an error compensation model by separating an error matrix of a tool tip from an error synthesis model of a multi-axis controlled machine, whereby the error compensation model compensates for geometric error of the multi-axis controlled machine; and calculating an error compensation value using the error compensation model and an inverse kinematic model so that the error matrix becomes an identity matrix; wherein the error compensation model is expressed by a following formula: 
 τ p,N t ( r C )=τ p,N t ( r N )[ E p t ( r C )]*, wherein r C is the error compensation value, τ t p,N (r C ) is tool posture which does not include an error of the r C , r N is a nominal value, τ t p,N (r N ) is tool posture which does not include an error of the r N , and [E t p (r C )]* is an inverse matrix of an error matrix of the error compensation value r C and is an approximate formula produced by omitting error terms from [E t p (r C )] −1 .