Observation of a Collective Oblate Band in ¹³⁷Ce

High spin states in ¹³⁷Ce have been studied by using the heavy-ion induced reaction ¹²⁴Sn（¹⁸O, 5n) carried out at China Institute of Atomic Energy. Partial level scheme with spin up to (43/2^-), including a high spin collective rotational band observed for the first time, has been established. The collective band shows the properties similar to those oblate bands with γ~ -60^o in neighboring nuclei and probably originates from the five quasi-particle configuration vs_l/2 vh_11/2² πg_7/2 πh_11/2. The characteristics of this oblate band have been discussed.