[Problem] The present disclosure provides tertiary amide derivatives substituted with a 4-membered ring structure that are useful as medicines and pharmaceutically acceptable salts thereof, pharmaceutical compositions comprising the same, and therapeutic agents and/or prophylactic agents for conditions in which CBP/P300 is involved, comprising the composition. [Solving Means] More specifically, the present disclosure provides a compound represented by the following Formula (1): wherein A represents CHF, or CH2, B represents the following Formula (B-1): Ring Q represents an optionally substituted 6- to 10-membered aromatic hydrocarbon ring, or an optionally substituted 5- to 10-membered aromatic heterocycle, Z represents —O—, —N(R7a)—, an optionally substituted 6- to 10-membered divalent aromatic ring group, an optionally substituted 5- to 10-membered divalent aromatic heterocyclic group, an optionally substituted 4- to 10-membered divalent non-aryl heterocyclic group, and R1, R2a, R2b, R3, R4, and R5 are as described in the specification, or a pharmaceutically acceptable salt thereof.