A compound represented by the following General Formula (I), a tautomer or a stereoisomer of the compound, a pharmaceutically acceptable salt thereof, or a solvate thereof, is used as a voltage-dependent T-type calcium channel blocker : wherein A represents a fused ring which may have a substituent, the fused ring being composed of a 5-membered heteroaryl group or a 5-membered or 6-membered heterocyclic ring and a benzene ring or the like, the 5-membered heteroaryl group having one to three identical or different heteroatoms as a ring-constituting element(s) having at least one substituent such as an alkoxy group having 1 to 8 carbon atoms and substituted with 1 to 5 halogen atoms; R represents a hydrogen atom or the like; B represents CR5(Q1) or NQ2, herein Q1 represents a benzimidazole group which may have a substituent; Q2 represents an alkyl group having 1 to 8 carbon atoms which may have a substituent, a heteroaryl group which may have a substituent, or the like; R0, R1, R2, R3, R4, and R5 each represent a hydrogen atom or the like; and n and m each represent 0, 1, or 2, provide that n and m are not 0 and 2 at the same time.