Background:Individualized nursing care is essential for patient-centered practice, yet few validated instruments exist in Japan for assessment from the nurse’s perspective. Purpose:This study aimed to develop and validate the Japanese version of the Individualized Care Scale–Nurse (JICS-Nurse) in acute care hospitals. Methods:A cross-sectional survey was conducted with nurses and midwives in Japan. Item analysis, exploratory and confirmatory factor analyses were performed. Internal consistency was assessed with Cronbach’s alpha, test–retest reliability with Pearson’s correlations and intraclass correlation coefficients (ICC), and concurrent validity with correlations to the Self-assessment Scale for Nursing Practice for Person-Centered Care (SSNP-PCC). Results:Valid responses from 536 of 705 invited participants were analyzed. A three-factor structure consistent with the original version was supported. CFA showed good fit for JICS-A and an overall acceptable fit for JICS-B, Internal consistency was high (α=.94), while test–retest reliability was moderate (ICC=.54 for JICS-A, .51 for JICS-B). Strong correlations with SSNP-PCC supported concurrent validity (r=.78 and r=.72;p<.001). Conclusions: The JICS-Nurse demonstrated reliability and validity and may be a useful tool for assessing individualized nursing care in Japanese acute care hospitals.