A circuit design supporting apparatus includes: an observation portion specifying section configured to specify a first portion with a high improvement effect of analysis easiness in failure analysis of an integrated circuit as an observation portion; and an element substitution performing section configured to substitute an element arranged in the observation portion by an analysis target element to which a failure analysis apparatus can appropriately conduct the failure analysis based on a data of the observation portion. The element substitution performing section includes a timing analyzing section configured to perform timing analysis of the integrated circuit shown by a netlist; a delay calculating section configured to calculate a delay in the integrated circuit based on a result of the timing analysis by said timing analyzing section and said netlist; a substitution element determining section configured to specify a fine element, which is arranged in said observation portion, of elements of the integrated circuit as a substitution candidate element; and an element substituting section configured to update said netlist to form a new netlist.