Axonal branching and elongation are stepwise processes essential for the establishment of functional neural circuits. Previous studies have shown that cAMP plays an important role in regulating axonal outgrowth: however, it remains unclear whether and how cAMP regulates axonal branching and elongation independently. To answer this question, we utilized photoactivated adenylyl cyclase (PAC), which produces cAMP either transiently or continuously depending on the exposure time to the blue light, for regulating the intracellular cAMP levels. In the primary cultures of dentate granule cells transfected with PAC, we found that the 10-min exposure of blue light induced axonal branching but not elongation, whereas the 30-min exposure of blue light induced both axonal branching and elongation. In PAC-expressing granule cells that were exposed to the blue light for 30 min, siRNA-mediated knockdown of protein kinase A (PKA) inhibited axonal branching but not elongation, whereas siRNA-mediated knockdown of exchange protein directly activated by cAMP (EPAC) inhibited axonal elongation but not branching. These results suggest that the intracellular cAMP regulates axonal branching and elongation via PKA and EPAC, respectively. Furthermore, our study indicates that the temporal regulation of the intracellular cAMP levels underlies the independent cAMP cascades-mediated axonal morphogenesis.