AbstractThis paper describes the problems, mainly from a standpoint of circuit stability, in the case in which we analyze and design analogue integrated circuits using a computer simulation program. Although a fundamental condition of an analogue circuit is whether DC bias can be determined stably or not, computer simulation is not good at this stability check and it is pointed out that an unstable circuit is sometimes checked to be stable accidentally. In the circuit partitioning process used in large‐scale integrated circuits, a risk that is shown in examples is that, depending on the manner of partition, its subcircuit may become unstable and it makes analysis of the whole circuit impossible. As an example we take SPICE, a representative program for analogue circuit simulation, to discuss the problem of default values in the program, direct current bias analysis, one that inside of a computer is assumed to be ideal, and the necessity of transient analysis. Then it clarifies the importance of correct modeling of circuit elements and careful usage of a simulation program after good understanding of its properties.