To provide a parking lot guiding system suitable for a park and ride (P&R) system.

This system comprises: a measuring means for measuring a passing traffic volume at a prescribed spot on a road leading to a prescribed parking lot; a creation means for creating a storage/retrieval pattern shown by time elapse of the storage state and the retrieval state of the prescribed parking lot; a prediction means for predicting the future number of parking cars in the prescribed parking lot by comparing the passing traffic volume measured at the present time with the number of parking cars in the prescribed parking lot determined from the created storage/retrieval pattern; and a guide control means for performing guide display of the full or vacant state of the parking lot on a display board provided on a prescribed position on the road leading to the prescribed parking lot based on the predicted number of parking cars.