The invention provides a multilayer sheet and a heat-treatable packaging material which have excellent flexibility, transparency, impact resistance, heat resistance, heat-sealability and cleanliness, which are endowed with a good formability without readily incurring drawbacks such as external defects and thickness fluctuations when subjected to multilayer formation, and which, even at a reduced thickness, have an excellent sheet substrate strength decrease-inhibiting effect. The multilayer sheet is a multilayer propylene resin sheet composed of at least two layers of an inner layer (1) and an outer layer (2), wherein the inner layer (1) is made of a resin composition (X) containing from 60 to 90 wt% of (A) a propylene resin composition which includes from 30 to 70 wt% of (A1) a specific propylene-±-olefin random copolymer component and from 70 to 30 wt% of (A2) a propylene-ethylene random copolymer component, from 40 to 10 wt% of (B) an ethylene-±-olefin copolymer, and from 1 to 25 wt% of (C) a propylene resin, and the outer layer (2) is made of a specific propylene resin composition Y. The heat-treatable packaging material can be obtained from the multilayer propylene resin sheet.
