A CBCM circuit is capable of separately measuring each component of a measuring target capacitance. A node (N1) is electrically connected to a terminal (P2) between the drains of PMOS and NMOS transistors (MP2, MN2). As a target capacitance forming part, a coupling capacitance (C.sub.c) is formed between the node (N1) and a node (N2). The node (N2) is connected to a pad (58) through the terminal (P2) and an NMOS transistor (MN3), and a node (N3) is connected to a terminal (P3) between the drains of PMOS and NMOS transistors (MP1, MN1). A reference capacitance (C.sub.ref) is formed at the node (N3) as a dummy capacitance. Currents (I.sub.r, I.sub.t) supplied from a power source to the nodes (N3, N1) are measured with current meters (61, 62), respectively and a current (I.sub.m) induced from the node (N2) and flowing to a ground level is measured with a current meter (63).