Diagnosing atrial myxoma in pregnancy is challenging because patients may present with non-specific symptoms that might be overlooked. The timing of non-obstetric operation usually depends on the nature of the disease, after careful consideration of feto-maternal safety, including the use of cardiopulmonary bypass and placental transfer of anaesthetic drug. A woman in her 30s at 18 weeks of pregnancy presented with recurring dizziness. She underwent successful myxoma excision at 20 weeks under general anaesthesia and cardiopulmonary bypass. The 6×5 cm myxoma was histologically confirmed as myxoma. Early detection of atrial myxoma in pregnancy is crucial, and a clinician has to consider the diagnosis of left atrial myxoma with mitral valve obstruction as a cause of severe dizziness. Optimal outcomes require multidisciplinary management. In this case, surgery during the second trimester of pregnancy enabled a full-term pregnancy with the patient's and foetal well-being and normal postprocedural echocardiography.