1. A virtual golf simulation device for a golfer to play golf on a virtual golf course realized by imaging processing, comprising: a sensor for sensing flight of a ball hit by the golfer; an image processor for processing an image of the virtual golf course and a simulated image of a flight trajectory of the ball sensed by the sensor on the virtual golf course; a database including a text storing part for storing text data corresponding to predetermined voice guides to provide voice guidance to the golfer; a voice converter for converting predetermined text data among the text data stored in the text storing part to voice; and a controller which simulates a flight trajectory of the ball on the virtual golf course according to the sensing result by controlling the image processor, predefines situations in which a virtual ball of the golfer is placed on the virtual golf course, and identifies a predefined situation generated by the simulating a flight trajectory of the ball on the virtual golf course to trigger voice guidance to the golfer, the controller extracting or combining the predetermined text data according to the identified situation, and outputting the extracted or combined text data as the voice guidance by the voice converter and a speaker, wherein the database further includes a voice data storing part for storing voice data, and the controller determines whether to provide general voice guidance irrespective of a play of the golfer or customized voice guidance relevant to the play of the golfer to the golfer, wherein the controller extracts predetermined voice data from the voice data storing part and outputs the extracted voice data as the general voice guidance by the speaker if the controller determines to provide the general voice guidance, and wherein the controller extracts the predetermined text data from the text data storing part and outputs the extracted text data as the customized voice guidance by the voice converter and the speaker if the controller determines to provide the customized voice guidance.