Dihydroquinazolinone compound or pharmacologically acceptable salt, and cell growth inhibitor

Provided is a cell proliferation inhibitor comprising a compound of the formula (1) or a pharmacologically acceptable salt thereof:wherein J1 and J2 each represent CH or N, with the proviso that J1 and J2 are not simultaneously CH; r represents 0 to 4; each R101 is the same or different when r is 2 or more, and R101 represents a C1-6 alkyl group optionally substituted with a halogen atom or the like; s represents 0 to 5; each R102 is the same or different when s is 2 or more, and R102 represents a halogen atom or the like; R103 represents a hydrogen atom, a C1-6 alkyl group, a C3-6 cycloalkyl group, or a C3-6 cycloalkyl C1-6 alkyl group; and R101 and R103 are optionally linked together to form a five- to seven-membered ring hetero ring when R101 is present at the 8-position.