There is provided a morpholine derivative represented by General Formula [1A] or a salt thereof.(In the formula, a ring A represents a ring represented by General Formula [I] * represents a bonding position Z2 represents CH or the like Z1 represents CR6 or the like R6 represents a hydrogen atom or the like X1 represents CHR7 or the like R7 represents a hydrogen atom or the like X2 represents CH2 or the like R1 and R2 are the same as or different from each other, and each of R1 and R2 represents a hydrogen atom or the like R3, R4 and R5 are the same as or different from each other, and each of R3, R4, and R5 represents a hydrogen atom, NRaRb, or the like and each of Ra and Rb represents a hydrogen atom, a C1-8 alkyl group which may have a substituent, or the like.)
